Headers for Packard V-8!

[WCraigH]

Now that I have your attention... <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

Actually, if things work out, I may engineer and produce a few sets. KevinAZ is possibly interested in a set for his 55 400, I'd like a set for my Panther, Turbopacman for his 56 Pat. Anybody else interested? Price and exact design TBD.

This is a "feeler" kind of post. Having said that, you should know that I have experience designing and selling custom design headers. I designed a Tri-Y style for the Gen-2 Firebird back in the 1970s and sold them thru my company at that time, H-O Racing.

Today, I jacked up my Pat and did some preliminary measuring and "eyeball" engineering for a 3-tube style header for it. The passenger side is "cake". Despite the "busy" nature of the driver side, fitting a 3-tube style (remember that the Packard center exhaust port is siamesed) to the driver side should be no problem. The only question is the maximum size of the tubing: 2x1.5&1x2 or 2x1.625&1x2.125 or 2x1.75&1x2.5. That will be determined later.

Comments solicited. <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

[Guest]

How about designing a set for my 356" staight eight. Is it true a set of small block headers will work on the engine with slight modification? It would be neat to have a dual exhaust on a 1947 Super Clipper. <img src="http://forums.aaca.org/images/graemlins/smile.gif" alt="" />

[bernardi]

Craig -

I'm definitely interested. If the price is right, two sets.

Incidentally, has anyone tried the exhaust systems offered on e-Bay by a Florida outfit? I know of one member of this forum who is unhappy with them, and wondered if other of their customers were unhappy.

[Guest imported_PackardV8]

Let me guess. The alleged Florida outfit is a "republican" with first initial "K" ???? I had some trouble with their exhaust too.

[Guest imported_Speedster]

Yes, the duel exhaust system I got on eBay for '56 Clipper had to be modified several places to get it to fit correctly: manifold down pipe on left side was about 2" too short, to mate at correct location. Next 2 pipes back (left and right) did not mate at hanger-clamp locations correctly and one rear muffler was not at correct angle. But for an exhaust system that is that complicated, with 4 mufflers and that many turns, bends and hanger-clamp points, I didn't expect it to be perfect. I expected I would have to do some cutting and welding to make it fit acceptable.

[Jack_Vines]

How about as long as we are going to do it, lets put in a divider for the center port. More than 40 years ago, we built four tube headers for the Cadillac, Oldsmobile and Studebaker V8s. They were absolutely necessary with long duration racing camshafts. The dividers were part of the header and fit back up into the center exhaust port. They were made just a 1/8th-inch oversize, so they could be file-fitted to ported heads.

While you are at it, make a set to fit the 1956 Golden Hawk. More Studebaker owners are into performance than are Packard owners.

thnx, jv

[Joe Block]

SO is the center tube over sized to manage the extra exhaust volumes. I am just curious as i don't yet own a Packard V-8

[WCraigH]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">How about as long as we are going to do it, lets put in a divider for the center port. (snip) </div></div>

In my experience, unless the headers are true equal length or real Tri-Y design (which both take advantage of tuned pulse effect) separating the center exhaust won't make much difference. The main problem I'm trying to "fix" with simple, convenience-fit headers is the inherent restriction of the stock log-style manifolds. Then an owner could put Flowmasters or whatever mufflers on his V-8 Packard for about a 25HP & 20TQ gain with no other mods according to Dyno2K numbers.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">While you are at it, make a set to fit the 1956 Golden Hawk. More Studebaker owners are into performance than are Packard owners.</div></div>

Well, if you'll get a 56J to Pahrump, NV and leave it for about 2 months for this project, then I'll do it! <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

[WCraigH]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">SO is the center tube over sized to manage the extra exhaust volumes. I am just curious as i don't yet own a Packard V-8 </div></div>

Yes. In theory for a 3-tube design, the center pipe should have twice the cross-sectional area (ID) of the cross-sectional area of each end pipe. However, this is not practical in the real world.

The Packard V-8 exhaust ports at the flange measure approx: end ports=1.1"wide x 2.0"high, center port=1.4"wide x 2.0"high. This corresponds to an area ratio of 1.28 (not 2.0)! The area ratios of some of the possible exhaust pipe diameter combinations are as follows:

end=1.5, center=2.0: 1.81:1

end=1.5, center=2.125: 2.05:1

end=1.625, center=2.125: 1.75:1

end=1.625, center=2.25: 1.96:1

end=1.75, center=2.5: 2.08:1

Another consideration is having the exhaust pipe inside cross-sectional area at least equal to the valve discharge area at maximum cam lift. For a stock Packard V-8 with 1.687" OD valve size and cam lift of approx 0.400", this is 2.19sq-In. The ID cross sectional area of common exhaust end pipes are:

1.5: 1.63sq-In

1.625: 1.92sq-In

1.75: 2.24sq-In

For the center pipe, the ID x-sectional area should be 4.38sq-In to match the 2 exhaust valves' area. The ID cross sectional area of common exhaust center pipes are:

2.0: 2.95sq-In

2.125: 3.35sq-In

2.5: 4.67sq-In

So, from an matched-area point of view, the best combo of exhaust pipe sizes would be 2x1.75" (ends) and 1x2.5" (center). These are the sizes of the tubes used on the old 3-Tube Hedman headers for early GTO, for instance, and no doubt most others of that type.

However, this presents a practical problem because of the relatively small size of the Packard V-8 center port. A 2.5" tube has an internal circumference of 7.66". The approx perimeter length of the center port (roughly rectangular with radiused corners) is 6.37". A closer match to this port would be the 2.25" tube which has 6.48" internal circumference.. The end ports and tube mismatch is similar. The perimeter length of the end port is approx 5.77" and a 1.75" tube has an internal circumference of 5.30". A better match would be the 1.875" OD tube which measures 5.70" internal circumference.

Finally, from a convenience fit point of view, the smallest OD tubes are the easiest, i.e., 1.5" OD ends with 2.0" center. However, this yields an area ratio of 1.81:1 (see above) and is only 78% and 71% of the max lift valve areas for the end and center ports, respectively.

This is no doubt more than you wanted to know, but are some of the engineering considerations that go into designing a set of headers. <img src="http://forums.aaca.org/images/graemlins/cool.gif" alt="" />

[bernardi]

Many thanks for the explanation of exhaust pipe diameter vs port size vs valve lift. It is information worth having, even if I never build a set of headers.

[WCraigH]

Addendum to :

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">How about as long as we are going to do it, lets put in a divider for the center port. </div></div>

After inspection on a spare head this morning, it appears that the limiting factor of the center exhaust port width is equally constrained by the head bolt holes and the exhaust manifold bolt holes. Allowing for 0.030" minimum wall thickness in the exhaust port, the maximum width possible of the center exhaust port is approx 1.7". This would yield approx 3.7sq-in (w/2.0in height). This improves the ratio of center to end port area to 1.55:1 (from 1.28:1 stock), but still pretty far from the ideal 2.0:1. Now, if you put a center divider in there, that will reduce the cross sectional area back towards stock. Any gain due to exhaust pulse tuning would probably be more than offset by the restriction. <img src="http://forums.aaca.org/images/graemlins/frown.gif" alt="" />

Due to the layout of the head bolt holes in the block, there's no easy way around this limitation. A proper solution would require an entirely new head design with relocated exhaust ports, such as what Pontiac did with the Ram Air V (Tunnel port) head. Not in this reality, for sure. <img src="http://forums.aaca.org/images/graemlins/tongue.gif" alt="" />

[Guest Randy Berger]

Let's not forget the need for a generator mounting bracket that must be very sturdy.

[WCraigH]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Let's not forget the need for a generator mounting bracket that must be very sturdy. </div></div>

Good point, but in the case of my Panther and KevinAZ's 400, we're going with 1 wire alternator which requires a different bracket yet.

[Guest]

Craig: Good Luck on your header venture, If I owned a 55 or 56 I sure would be putting in my order. What has to make me laugh is the quote from a PIC member in another thread in this forum saying something that only the best Packard mechanics belong to PIC or PAC. What you fellows are doing is to me far more than anything PIC or PAC has to offer on solveing some of the problems with 55 and 56 Packards.

[Guest Rojo22]

Ok, I have a question, and you guys can laugh all you want, I am not mechanically inclined, and you can shove what I know about engines into a needle eye and have enough room for thread. If there are three holes on the headers, and one hole is "shared" by the middle cylinders, wouldnt the timing and exhaust be such that the single hole would be sufficient for the exhaust since both the middle cylinders wouldnt be exhausting at the same time? Again, please pick yourselves up off the floor, I got thick skin and am willing to learn, so please edjumcate me...LOL....