Packard V8 Performance Capabilities

[Guest]

Greetings, All,

In the standard transmission thread, a separate discussion began regarding the performance capabilities of the Packard V8. I thought it might be useful to have this in its' own subject/title.

IMHO, the Packard V8 came with a lot of cast iron for the money. However, as it came from Packard, it had two fatal flaws which caused failure when run hard.

The first was the well-known and thoroughly discussed oil pump and oiling system weaknesses.

The second is the large, long and heavy valves. They are longer, at 5.7", than most any modern V8. The heads of the intakes at 2" are also quite large. The stems are 3/8" diameter, where Chevys of the same head size are 11/32". The standard springs, with only 90# of seat pressure, were unable to control them at high rpms. Usually, the hydraulic lifters would begin to pump up at around 5,000 rpms anyway.

Most sucessful Packard racers (usually the Studebaker Golden Hawks) converted to an Iskenderian solid lifter camshaft, adjustable pushrods and much stronger valve springs. So equipped, the Packard V8 would rev to 7,000 rpms.

If the oil pump was reasonably new, if the oil was clean, the engine would last a few quarter mile runs at these rpms before wiping out the center three main bearings.

Also, FWIW, I am building a performance Packard V8 with titanium 2.180" intake/1.6"exhaust valves, titanium retainers and keepers to reduce the valve train weight and a solid roller camshaft with Jesel roller tappets.

I am also going to run a dry sump oil system to keep pressure up. A concern is the unknown quality of the white box rod bearings from Egge Machine.

Would really appreciate a lead on a forged crankshaft!

thnx, jv.

[WCraigH]

Wow! Titanium valves? dry dump oiling?

What about porting on the heads? What are you going to do about the siamesed center exhaust port? What about the intake manifold and the log-style exhaust manifolds?

Packard-buddy Paul in Las Vegas has run Isky solid lifters, springs and adjustable push rods since the 1970s. He also reports 7000 rpm capability. But the HP is all done at 5500, so what's the point without the above mentioned breathing enhancements?

An old racing friend of mine is Pete McCarthy, a nationally known Pontiac engine performance expert who has written 2 authoritative books on the subject and sells a head porting how-to video. A few years ago, he flowed my 1955 Patrician cylinder head on his flow bench. It performed similar to a 1964 GTO (1963 Pontiac 421) cylinder head. As you may recall, these Pontiac engines were all done at low 5000 rpm, but great on torque due to intake port velocity and other engine parameters. To expect more power (rpm) out of the Packard V-8 without extensive, knowledgeable head porting, is unreasonable.

[Guest imported_PackardV8]

56J, how far are u from Nashville Tm.????

[55PackardGuy]

RE-POST

Just thought I'd stick that post from the tranny thread here. Sorry, should've just started a new one:

Quote from PackardV8:

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">The Packard V8 engines are capable of very high rpm due to the massiveness of its internal parts.</div></div>

There's been a lot of talk about how the "over-built" Packard V8 has a lot of potential for cid, but not much about RPM capabilities. Just how massive are the internals? Any comparisons of piston/rod/crankshaft/bearing specs with other engines?

Also, does anybody have experience with how much RPM these engines would potentially take? I've never heard of one "throwing a rod"--ever. Just some weakness in the valve-train, specifically springs. Just wondering.

Craig answered:

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">For contemporary comparison, see:

Packard V-8 vs the competition

The high rpm capabilities of the Packard V-8 come from its relatively short stroke (3.5in) compared to bore (4+in), relatively small main and rod bearing diameters, forged rods and last, but not least, the rocker shaft style valve actuation, as opposed to the stud-rocker ball style of the SBC and Pontiac V-8s of the same era.</div></div>

Craig,

The "over square" bore and stroke are a natural for high RPM applications. Just out of curiousity, were some of these valve train tricks carried over from aviation or marine engine designs?

[Pontiac59]

I myself am now curious - it seems these blocks have some meat to them that it might be possible to save a block even with some rust inside. Can a 352 block be bored to a 374 if say .030 won't clean it up? Sometimes it is also cheaper to get stock bore pistons for the next larger stock bore than overbores. No idea what to expect if I get into this engine, but it seems like a good motor to build given an ability to run to 5000 RPM, if you don't beat on it too much. Valves may be another story, although I suppose one could look at changing guides if there are better valves with a long enough stem available for some other application.

[WCraigH]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">(snip) Can a 352 block be bored to a 374 if say .030 won't clean it up? Sometimes it is also cheaper to get stock bore pistons for the next larger stock bore than overbores. (snip) </div></div>

Yes. I have bored my Panther 352 to 374; sonic tests showed plenty of cylinder wall thickness. Paul in 'Vegas has done the same. An article from Hot Rod Mag in the period documented +0.125 overbore of a 352 in a 56J buildup.

The 374 bore size is the same as Chevy (and others), which means you can get custom pistons from any of the hot rod manufacturers relatively cheaply. Also, many engines use that bore size, so rings are no problem.

[WCraigH]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">(snip)

Craig,

The "over square" bore and stroke are a natural for high RPM applications. Just out of curiousity, were some of these valve train tricks carried over from aviation or marine engine designs? </div></div>

I expect that the rocker shaft design was quite well known at that time (late 1940s when the Packard V-8 was designed) for it's stability and strength. It was a design choice completely in line with Packard's "over engineered" philosophy.

It was the rocker-ball stud style that was innovative. Chevy & Pontiac got a lot of cudos for it at the time, although I don't know which GM division came up with it--maybe cross polination. The Chevy and Pontiac varients are not exactly the same, BTW. Anyway, it works really well in stock applications but don't try 500+lbs of open pressure unless you fit a stud girdle and use roller rocker arms!

[Packard8]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Speaking of design tricks, after a quick tour of the comparison tables at Craig's "1956 Packard Panther" site, I'd like to know what it was that Chrysler had in their V8 that let them develop more HP with less displacement - though the Packard V8 developed more torque. </div></div>

In a nutshell...hemi heads!

[Guest Randy Berger]

Aah Brian - you mean you don't believe Chrysler's marketing dept??

By the way Packard reached 405 ft lb at 2800 rpm. The 300B only reached 385 ft lb at 3200. If memory serves they were also running dual four-barrels. Anyone confirm this??

YFAM, Randy Berger

[Packard8]

Yep, dual quads on the hemi. I?m not sure if the early models had the cross ram intakes or not, but the later ones did. I think the better breathing (plus larger valves?) of the cross-flow hemi head design would account for the higher claimed HP. Volumetric efficiency is the name of the game at high RPM.

As I recall the SAE or some similar org tested and rated the engines. My uncle worked for Buick during the 50?s and he witnessed some of the tests. He said they were basically bare motors (carefully selected by the factory) hooked up to a dyno with no fanbelt driving the waterpump or generator. They would start and run them wide open until the valves would float or the motor would grenade itself. Whatever the dyno printout said is what the mfg could claim. In reality, I?m guessing a showroom car produced 20-30% less than the claimed output.

[Pontiac59]

Reading this thread I'm inclined to wonder what, if any, solution has been come up with to solve the oil system issues? I wouldn't imagine you can go to Melling and pick up an 80 PSI oil pump for the Packard just like that.

Incedentally, in '57 the Daytona Beach speed trials were won by a Chrysler 300 only because the Pontiac that came in first was DQ'ed. Anyone have '56 results somewhere?

[WCraigH]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">(snip) I'm thinking that carving out such a path, plus bushing the bore for the driving shaft and truing or replacing that shaft is all that is needed to make a reliable pump - fit for even a daily driver (not just trailer queens). </div></div>

Brian, I agree that these oil pump mods are sufficient for a daily driver.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">

When it comes to performance purposes, I doubt if there was ever an HD oil pump (since this V8 was in production for not quite two years), but seem to recall that <span style="font-style: italic">CraigH</span> was working on some sort of substitue for his Panther, but it was not a dry sump that was mentioned earlier in this thread. The latter is geared toward extreme racing. </div></div>

There was no HD pump for the Packard V-8 that I am aware of. Pontiac had several varieties of oil pump for their V-8 including the Ram Air V -derived 80psi pump for the 1973-74 455SD.

Rather than take this thread somewhat off topic, I am starting a new thread to give a preview of the oil system mods for my Panther V-8.

[Packard8]

Hi Brian,

To oversimplify, HP is made in the top-end of a motor?the bottom end (block, crank, piston, rods) are just there to get it to the flywheel without self destructing.

For example, look at a modern NASCAR motor. I believe the cid limit is 360 cubes and they are basically the same decades old design as a 55-56 Packard ?.an OHV pushrod V8. However, they are making 800+ HP naturally aspirated with a single 4bbl carb while spinning 9000 RPM. This is accomplished via cylinder head design, intake and exhaust flow, camshaft duration, lift etc. Incidentally, when Mopar revived the 426 hemi in the 60?s, NASCAR banned it from the track because it was running circles around anything Ford or GM could field at the time.

The Packard V8 has a lot of potential, but the problem is the lack of aftermarket HiPo parts (for the obvious reasons).

[Packard8]

I?ve never actually seen one broken down, but I?m told that the Nash/Hudson variant had a totally different oil pump, and also a forged steel crank. Might be something to look into for building up a high output Packard V8. I don?t have the shop manual in front of me, but as I recall all the V8?s (320, 352, 374) had the same stroke.

[Guest]

In 1956 the Chrysler 300B was rated at 340 horse power. With the power to wieght ratio the Chrysler 300 B had over the Packard Caribbean it would have been no contest as the Chrysler wiehged in at 4360. The Packard Caribbean and 400 series weighed in at 4960 and 4590. In those days the 300 series was king of the walk. In 1956 the 300 B set the World Passenger car Speed Record at Daytona Beach averaging 133.9 mph.

One of the many design flaws of the Packard V8 that you fellows over look is that the engine weighed to dam much. The Packard V8 weighed in at over 850 lbs if my memory serves me right. It was only 6% lighter than the straight eight it replaced. If Packard would have gone into production in 1957, the engine would have gone to over 400 cid, thats how much meat this engine had.

While putting the Packard V8 into a Studebaker Hawk was a great idea on paper, one of the big knocks and ccomplaints against the Packard Hawk was that she was nose heavy, and did'nt handle worth a dang, and had poor braking as well.

One thing more that I would like to say about the 300B that with the optional compression ratio of 10 to 1 she was good enough to produce 355 hp. In 1956 if I was in the market for a performance car it would have been the 300B and certainly not the Caribbean

[55PackardGuy]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">hooked up to a dyno with no fanbelt driving the waterpump or generator. They would start and run them wide open until the valves would float or the motor would grenade itself. Whatever the dyno printout said is what the mfg could claim.</div></div>

I think this is what was appropriately referred to as "gross" hp. <img src="http://www.aaca.org/ubbthreads/images/graemlins/shocked.gif" alt="" />

[Packard8]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">

One of the many design flaws of the Packard V8 that you fellows over look is that the engine weighed to dam much. </div></div>

No dispute here that the 300 was the faster car?simple physics. However, the hemi motor was no lightweight?those heads were HUGE!!! There was a reason they called it the ?Elephant Motor?. <img src="http://www.aaca.org/ubbthreads/images/graemlins/wink.gif" alt="" />

[Guest Randy Berger]

I don't think we're overlooking the weight, and in the Hawk body the front-end plow will quickly check your adrenalin pump. 56JPackard can probably confirm this.

The V8 engine dry weighed in at 698 pounds with all accessories except air cleaner - radiator complete with core and tank was 22 pounds.

The 359 straight-8 weighed 752 pounds. The radiator weighed 32 pounds.

ref: "The New Packard V-8 Engine" by W.E.Schweider Packard Division S-P Corp.

I would like to see like figures for the Chrysler engine. The Packard was designed with growth in mind. Chrysler had already had a couple engine changes from 1951 to 1956. The same 354 was used in the New Yorker, Crown Imperial, and Imperial with HP differences from 280 to 340.

I still think that Packard did a fine job given the number of engines built versus the problems encountered. Just my opinion.

YFAM, Randy Berger

[Packard8]

I don't think we're overlooking the weight, and in the Hawk body the front-end plow will quickly check your adrenalin pump. /quote]

The Stude V8 was a pretty meaty piece itself..around 650 lbs I think. The problem with all Stude C/K bodies was the infamous ?rubber frame?. They finally had it stiffened up by the time the last GT Hawks were built.

Contrary to popular legend, I think it was the fact that the Packard engine line had shut down that resulted in the switch to the Stude 289 V8 in 1957 Golden Hawk?. more so than the weight of the Packard V8.

[Guest]

Brian: Could have the Packard Caribbean ever competed with the 300 series Chrysler, I real doubt that they could have ever competed. In 1957 the base 392 engine on the 300C pumped out 375 hp at 5200 rpm's. There was also an option engine for the 300C a 392 which was rated at 390 hp, this baby had headers, solid lifters,10 to 1 compression ratio, and 2 1/2 low back preasure exhaust system. No torqueflite trany with this engine only a three speed standard.

[Packard8]

Of course it?s all speculation, but?.. Had Packard remained viable, I?ve read that they had plans to grow the V8 to 440 cid. Add a more aggressive cam and valve train, larger diameter exhaust and drop it into the 1959 Panther (based on the lighter weight short wheelbase ?59 Constellation HT coupe) ???. Well, you get the picture (right WCraigH)?

Or put that 400+HP motor in the ?59 Packard Hawk Daytona (based on the 3500# Stude GH and available only with the new Borg Warner 4 speed manual) and go set some records!!! <img src="http://www.aaca.org/ubbthreads/images/graemlins/shocked.gif" alt="" />

[WCraigH]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Of course it?s all speculation, but?.. Had Packard remained viable, I?ve read that they had plans to grow the V8 to 440 cid. Add a more aggressive cam and valve train, larger diameter exhaust and drop it into the 1959 Panther (based on the lighter weight short wheelbase ?59 Constellation HT coupe) ???. Well, you get the picture (right WCraigH)? </div></div>

Very interesting!

The 1957 440CID Packard V-8 (one off in "Black Bess") was most likely a +.060 374 (4.185) stroked +0.500 (to 4.000).

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> Or put that 400+HP motor in the ?59 Packard Hawk Daytona (based on the 3500# Stude GH and available only with the new Borg Warner 4 speed manual) and go set some records!!! <img src="http://www.aaca.org/ubbthreads/images/graemlins/shocked.gif" alt="" /> </div></div>

The model for this migration path is Pontiac with their Super Duty engines from 1959-63. Although Pontiac's block dimensions are smaller than Packard (almost everyone's are), the cylinder heads are quite similar in layout and flow. So what Pontiac did in NHRA and NASCAR (then Grand National), Packard could have also done, if so motivated and if funds were available in this [color:"red"] altnernate reality.

For instance, a +.090 Pontiac 421 is exactly the same bore/stroke as the Packard 440 I defined above. Pontiac had single 4bbl, 3x2bbl and 4x2bbl intake systems. Pontiac developed special cylinder heads that flowed more than the stock variety and used slightly larger and polished valves. Pontiac also had streamlined (header like) exhaust manifolds in both cast iron (GN) and aluminum (NHRA). Pontiac's Malcolm McKellar developed a series of mechanical tappet camshafts for racing. Ed Iskendarian, Sig Erson and others produced camshafts in both mechanical flat tappet and roller grinds in that era. The Pontiac 421SD NASCAR engine was advertised at 405HP (painted on the hood of the race cars), but probably produced a [color:"red"] LOT MORE (like 500HP).

So a Packard 440CID could have matched this performance engineering because it was all straight forward and logical extensions of the stock motors. Packard V-8 could have also grown to 500CID (like the Caddy), if required (see previous thread on comparative bore size).

And don't forget Fuel Injection and super charging! Mickey Thompson, Don Gay, Arnie "The Farmer" Beswick and others built Pontiac-powered dragsters including top fuel "rail jobs" that made well over 1,000HP.

Ah, that would have been an interesting [color:"red"] alternate reality! <img src="http://www.aaca.org/ubbthreads/images/graemlins/grin.gif" alt="" />

[Pontiac59]

I'll say they look like the Pontiac. So much so that I started to pick up a loose intake manifold in my friend's garage, thinking it might be a Pontiac and wondering why he had it in there (!)... when it was one of several Packard intakes all in a group there.

I think if I had more time to run the numbers, I'd theorize a potential ultimate performance for the Packard motor based on the percentage of improvement over time for the Pontiac motor and compensate for various higher cubic inch displacements. To make it more fair, one might run numbers for a couple of other engines and determine an average figure for the improvement in performance/power.

[WCraigH]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I'll say they look like the Pontiac. So much so that I started to pick up a loose intake manifold in my friend's garage, thinking it might be a Pontiac and wondering why he had it in there (!)... (snip)</div></div>

Been there, tried that with a Pontiac intake on a Packard cylinder head. Everything lines up pretty close except that the #1 (Driver side) cylinder in a Packard V-8 is forwardmost in the block and the #2 (Passenger side) cylinder is forewardmost in a Pontiac V-8 (ass backwards and nobody knows why). This eliminates the possibility of adapating a Pontiac 3x2 or 2x4 intake to the Packard.

From pictures, it seems like the Chrysler 383-413-440 intake might work, but I haven't been able to locate one (free) for comparison. If so, several aftermarket manufacturers (Edelbrock, Offy, Weiand) offer 2x4 aluminum intakes for the Chrysler. This might be a "cheap" way to emulate the Caribbean 2x4 setup.

[Pontiac59]

I'll have to pull one off one of my '60 Chrysler parts cars and plop it on a Packard - my friend there has several with intakes off - and see how it lines up. I'd just send you the intake but the shipping will be crazy -

[WCraigH]

That would be cool. Let me know one way or the other.

[WCraigH]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">(snip) When it comes to Chrysler's further developments for '57, in the absence of a Detroit-engineered and -manufactured '57 Packard (not the South Bend "replicars"), has anyone taken the specs for the proposed 440-cid Packard V8 and run them on any computer simulation software like <span style="font-style: italic">Desktop Dyno</span>? </div></div>

Yes, I have that software and did some simulations a few years ago. Here's what it indicated:

1956 Caribbean 374CID 2x4bbl: 309HP-4500, 404TQ-3000 (nearly identical to advertised HP & TQ)

1957 440CID 2x4bbl: 309HP-4000, 466TQ-2000 (displacement increase only, otherwise same as 1956)

Increase valve size 10% to 2.11 intake, 1.77 exhaust (same as Pontiac 1967+): 324HP-4500, 469TQ-3000.

Increase cam timing 10-deg on both and lift by 10% on both to allow for the increase in CID: 343HP-4500, 454TQ-3000.

The latter is the same HP but more torque than the 1957 392CID Hemi in the Imperial, but short of the 300C's 390HP.

Bumping the Compression ratio up to 10.50 bumps the HP up to 351HP-4500.

Installing an Isky-style solid lifter cam (like the 300C) yields 375HP-5000, 450TQ-4000.

Installing slightly ported heads (like the Pontiac SD series) yields: 412HP-5500, 462TQ-3500.

So, according to the Dyno 2000 simulator, the performance potential is certainly there. At 440CID, this engine would still idle reasonably and pull a heavy Packard off the line because even this last combo has 412TQ-2000!

Now this is a [color:"blue"] simulated [color:"red"] alternate reality! <img src="http://www.aaca.org/ubbthreads/images/graemlins/grin.gif" alt="" /> <img src="http://www.aaca.org/ubbthreads/images/graemlins/grin.gif" alt="" />

[WCraigH]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">(snip) Have you run simulations that limit the displacement to 374 to see what improvements might be done for your Panther Project, in various stages of increasing complexity? For instance, start with simple porting, then larger valves, then an "available" Isky cam (of the period), and then different "custom" cam profiles. I'm just curious as to what might have been <span style="font-style: italic">reasonably</span>possible for '56. </div></div>

Yes. The 374CID Panther engine has a 625CFM Edelbrock Performer (nee Carter AFB) carb, Lazer hydraulic cam (275/280, .491/.496) and deburred heads simulated 360HP-5000 according to the D2K software.

A "hot street" version with 2x4bbl carbs, small tube headers, ported heads and mechanical flat tappet cam (262/270, .450/.450) simulated 450HP-5500. The big jump in HP would be difficult to achieve in [color:"red"] this reality since headers are physically difficult to fit because of the T-L and nobody has any experience porting Packard heads.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> BTW, when it comes to the "future" for Packard, I have some copies Advanced Engineering notes (probably from some monthly meeting) that indicate that the emphasis for engine development (at least late in the 1955 calendar) was on fuel injection - citing increased maximum torque at lowere RPMs with a flatter curve, though with just a slight increase in HP. Mind you those notes are very sketchy - no specifics. </div></div>

At least we have reason to believe that this was real because of the pic on the PI website showing an FI prototype on the V-8. We also know that those mechanical FIs of the era (Chevy, Pontiac) were very problemmatic.

[Packard8]

Craig,

Have you run any simulations with forced induction? Visually it looks like a center mounted Paxton/McCulloch would fit in the valley, as was the case with the 57-58 Hawks, 57 Clippers & the later 63-64 Hawks & Larks.

I understand that newer/better brgs are now available which would allow greater pulley overdrive ratios and higher impeller RPM?s and perhaps feed 5-6 PSI to the 374.

Another plus is that it would have the original ?Packard Supercharged? crest on the blower. <img src="http://www.aaca.org/ubbthreads/images/graemlins/grin.gif" alt="" />

[WCraigH]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Craig, Have you run any simulations with forced induction? (snip) </div></div>

No, not on the Packard V-8. I've run several on turbocharged Pontiac 350, 400 and 455.

I haven't run the Packard V-8 because my Panther 374 has 10:1 CR, which is too high for super/turbo- charging. It would be cool though to build the right motor (8:1 CR) and fit one. However, I wouldn't do it without first fitting EFI and getting that to run right. There was a previous thread on EFI, if you haven't seen it.

[Packard8]

However, I wouldn't do it without first fitting EFI and getting that to run right.

EFI would be a quantum leap, but blow-thru carbureted super/turbo-charging is pretty doable with computer controlled ignition/timing controls. J&S and MSD have modules with O2 and knock sensors that can advance/retard (or ?switch off?) each cyl (or all) on a nano-second real time cycle. These little gadgets don?t really care if they are hooked up to a turbo?d 20 PSI twincam ricer or an old Packard straight 8?. They just process the input parameters and control the spark accordingly.

Yes, your stock 10:1 pistons would be a limiting factor (tho many Chevy LT-1?s are running 10:1 C/R with 8 PSI ProChargers).

I?m sure Ross, Venolia or KB would be glad to make you up a set of 8:1 forged Pi$ton$?.

[Guest]

Greetings, All,

Thanks to everyone who has contributed. Here are my latest findings.

1. Packard head intake ports. I just had the stock Packard intake ports compared to a professionally ported Pontiac 421 head. The Packard head out-flowed the Pontiac. The difference was when an intake was added. There are many Pontiac aftermarket intakes with years of development behind them. The good aluminum intakes only dropped the Pontiac flow by 15%. The stock iron Packard intake dropped the Packard flow by 25%.

2. Big Bloc Mopar intakes have the ports slightly closer together, but that is not the deal-breaker. They have a 70 degree mating angle, while the Packard uses 90 degrees. I cut the Mopar intake into four sections, aligned everything and welded it back together. This requires remachining the carb mounting surface, welding a new plate on top and drilling/taping new holes. After all this work, it still does not flow as well as it did on the Mopar. Next time I would build a sheetmetal manifold.

3. Exhaust ports are still the weak link. The engine is so wide, there is no room left for efficient headers. On a '56J, the front two cylinders almost hit the inner A-arms. Without cutting into the fenderwells. headers don't fit.

4. The Packard can be made to run with any original '56 block/head US V8 out there, but it will cost more to make it happen than would the Chrysler or Cadillac - the only real competition back then.

thnx, jv.

[WCraigH]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">1. Packard head intake ports. I just had the stock Packard intake ports compared to a professionally ported Pontiac 421 head. The Packard head out-flowed the Pontiac. The difference was when an intake was added. There are many Pontiac aftermarket intakes with years of development behind them. The good aluminum intakes only dropped the Pontiac flow by 15%. The stock iron Packard intake dropped the Packard flow by 25%.</div></div>

I completely agree. Several years ago, I had the worn out head off my 55 Pat flow tested by Pete MCCarthy, probably the foremost Pontiac Engine historical performance expert in the world and also an old racing buddy of mine. That head flowed about the same as a 1963 421 HO or 1964 GTO Pontiac head. Yup, the intake manifold is obviously the problem.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">2. Big Bloc Mopar intakes have the ports slightly closer together, but that is not the deal-breaker. They have a 70 degree mating angle, while the Packard uses 90 degrees. I cut the Mopar intake into four sections, aligned everything and welded it back together. This requires remachining the carb mounting surface, welding a new plate on top and drilling/taping new holes. After all this work, it still does not flow as well as it did on the Mopar. Next time I would build a sheetmetal manifold.</div></div>

Interesting info. I did a similar thing in the 1970s to adapt an Edelbrock SBC "tunnel ram" intake to a 1956 Pontiac with 1970 Ram Air IV heads. Similar problem with intake surface angle between the SBC and Pontiac. See this for the result:

SBC Tunnel Ram on Pontiac V8

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">3. Exhaust ports are still the weak link. The engine is so wide, there is no room left for efficient headers. On a '56J, the front two cylinders almost hit the inner A-arms. Without cutting into the fenderwells. headers don't fit.</div></div>

On the 1955-56 T-L Packards it appears that the T-L bar and link are in the way so that even "block hugger" type headers are not really feasible.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">4. The Packard can be made to run with any original '56 block/head US V8 out there, but it will cost more to make it happen than would the Chrysler or Cadillac - the only real competition back then.</div></div>

Putting aside the $$$$, what about having a cylinder head with the same bore spacing (5") CNC machined by one of the top aftermarket suppliers? That way, it would have the latest technology, yet bolt right up to the Packard V-8. Oops, that doesn't solve the header interference problem.

[Guest]

Greetings,

If one were starting a clean-sheet Packard V8 head, it could be designed with a much higher, more vertical exhaust port exit, which would at least clear the '56J chassis, but then, we'd just have an overweight SBC.

thnx, jv.

[hairyclive25]

late but new info

BB Chrysler (383/440) manifolds will drop on with a little cut and paste work

https://forum.hetclub.org/discussion/122452/better-performance-parts-352-packard

 

sleeving the blocks and using the the full potential of the 5" bore centres allows 4.85" bores with siamesed sleeves, lots of pistons in that size now

with a 4.5" stroke and the large bore this makes 665 cu in

 

stock heads can be ported to give 300 CFM probably more with some welding and grinding 

The Iron Lung: Vintage Packard V8 Pumps Out 445 hp On The Dyno

 

There is no reason an engine that large couldn't be capable of reliable 600-750 hp with the correct mods, custom ground cam, and good internals if the block is strong enough not to break; the 427 tunnel port ford made 630 hp stock with mild porting est flow  330 cfm

 

 

the larger engine would make similar power probably about 4-5000 rpm with more available depending on good the bottom end could spin

Edited October 5, 2023 by hairyclive25
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