Red Dawn

1956 Model 48 322 upgrade

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First time here. I am looking at the possibility of switching out my 322 nailhead and dynaflow tranny with a rebuilt 401 nailhead. What transmission should I use with the 401 nailhead if I want to convert to a 4-speed? Do I have to use a different drive train and rear end by making this conversion? Do I have to make any adjustments to the gauges I am currently using. What other things should I consider before I begin this journey? Any advice is much appreciated. Thanks

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It's been done before, but nothing easy about it.  Here is one that works:  http://forums.aaca.org/topic/188651-modified-54-skylark/

Not a 4-speed, but that would not be  problem after you solve all the other problems.

Don't discount that 322 with Dynaflow unless both are broken beyond repair.  With a 4 barrel and dual exhaust it was rated at 256hp and that can be improved upon; the dynaflow is a switch pitch transmission that works in low range too...if you can hook up nobody can beat you off the line.

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Old Tank,

Thanks for the reply back. No, my 322 and Dynaflow work just fine, minor leaks though. I already have a 4-barrel and dual exhaust but, I compete in the modified class for car shows and am getting tired of being beat by all those crate engines. So, I wanted a boost in horsepower and get some cosmetic touches on the engine also. What are some of the problems that I need to be aware of?

Thanks,

Mark

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These conversions have happened. I know of one where a 56 Special was worked on for ten years before it was driveable. But I think the conversions have been well documented and are becoming more popular.  You can probably reduce the amount of time the car will be sidelined based in direct relation to the amount of money you are willing to throw at it.

 

As for what you may have to change, I suggest the rear axle and suspension plus the master cylinder and proportioning valve. Not to mention there were not a lot of 401's with 4 speeds, so you'll need to be on the lookout for the bellhousing, and then whatever fits behind that will probably require a custom trans cross member and mount.  Oh yeah, motor mounts, radiator, some electrical components.  Not too bad except when you consider how unique the car already is, seems unlikely the crowd you are seeking to impress will even know the difference between the 322 and the 401. 

 

I have seen some engine dress up items are being produced for the 322.   Aluminum raised rib valve covers and likewise spark plug covers.  Then you can always have some items chromed under there too for some extra shine.  Have a custom radiator built to lower it and increase coolant capacity.  All types of things can be dome to provide some WOW  under there while still maintaining a car you can drive today.

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For the trans, did you mean "4-speed" as in THM700 automatic or as in manual trans and clutch?  I suspect its the former rather than the latter.  OR . . . .a 4L80 (THM400 w/OD, non-electronic)?

 

To upgrade what you already have . . . you can replace the carb with a self-learning EFI system.  Upgrade the ignition to a good electronic system (which will need to be compatible with the EFI system).  I think that Wilwood has a disc brake conversion kit, which might also need some new hydraulics (master cylinder and power booster).  Check into a larger front sway bar and adding a rear one.

 

For the a/c system, there is an aluminum a/c compressor (by Denso?) that mimics the GM A6 compressor in all aspects, so finding some factory a/c brackets and the a/c kit itself can make the car more liveable.  Might even add an Ididit steering column with electric power steering!

 

I concur on using some of the period-correct underhood  "dress" items.  Aluminum finned valve covers would be nice, whether the aftermarket ones or possibly the ones like came on later Buick 425 V-8s.  Of course, you can replace the engine-driven cooling fan with a quality electric unit, if desired.

 

Now, what I've mentioned will not really "mess with" the many unique mechanical things which made Buicks "Buicks" back then, mechanically.  You'll still have a smoooooth cruiser and with the a/c, brake, and power steering upgrades, one that would be easy to drive AND be reliable.

 

Now, to really support and support the "crate motor" orientation of others, you can get an aftermarket frame and slide under your Buick's body.  It'll be stouter than the factory frame and also have all of the necessary things to support the late model powertrain items.  Plus totally unique suspension items that won't be available at the local auto parts store.  Just think of how your spending might help the nation's economy!

 

I spoke with an older gentleman who was trying to sell a recently-rebuilt Nailhead and DynaFlow.  He'd pulled them out and replaced them with a Chevy LS-family crate engine, modern fuel system, GM automatic trans, and such.  He wanted the Buick but also wanted something he could drive anywhere and not worry about it (after all, the crate engines have a GM factory warranty on them).  He had the money to have it all done, too, and not miss it (the $$$$$). 

 

To me, the car will ultimately be worth more the closer to stock it is.  The upgrades I mentioned would be aligned with that orientation, but also have enough upgrades (some from the pages of "Street Rodder" magazine) to get the interest of those that really cared.

 

The "minor leaks" you mentioned might be considered "normal" to many in here, for what it's worth.  But some modern silicone sealer in the right amounts and right places might help minimize them.

 

Also, if I was going to look to buy a '50s car, I'd want one with the factory-oriented powertrain in it.  That way, I'd know what I had AND could claim bragging rights that I didn't follow what others were doing, but did something better and unique that preserved the original character of the car.

 

Check out www.GreeneHDProductions.com website for the series on rebuilding a '55 Buick Special.  There were a few things I would have liked for them to have done differently (the a/c compressor, for example), but the car came out fantastically great in cosmetics, driveability, and WOW-factor.  It will hold it's own parked next to a "crate-engine" modified car, hands down!  Modified but does not scream "modified".

 

NTX5467

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More dress up items like 3 deuce setups are out there (looks only since it will not improve the performance).

Maybe I have never ridden in or driven a well done one, but all give an unpleasant experience compared to original:  the ride is rougher with unexpected kicks and jolts; drivetrain vibration is transmitted through the seat and steering.

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I think the biggest thing is that regardless of the choice of drivetrain, it has to all work together. As has been said before, if you solve one problem, you create three more. That is one reason why Willie hasn't ridden in a good one. The really good ones are generally really expensive. I would love to ride and / or drive Fins' Skylark. He seemed to really work out some of the details well. The main engineering point is designing a differential that works well and is smooth (not bumpy) with an open driveline.

FWIW, all Nailheads use the same valve cover so all aftermarket covers will work. The 56 has a rag joint in the steering column making a PS swap easier.

The real advantage in these swaps is that I get a lot of working parts for restoring cars for cheap or free.

Wanna get rid of those original parts? I might take em if they aren't too far away.

Oh yeah, one last thing. Please share what you do. I actually really like modified cars.

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On possible modification of the 322:

 

The offenhauser catalog shows a dual four-barrel intake manifold available. Might (or might not, don't know) be difficult to find.

 

If you can find one, definately would be easier to set up a set of quads than change the drive-train. And while three two-barrels are eye-candy, dual four-barrels WORK as well as eye-candy. Throw on a repro Ford (mill off the FoMoCo) air cleaner with the aluminum top (polish), and the 322 would look pretty snazzy!

 

Jon.

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On possible modification of the 322:

 

The offenhauser catalog shows a dual four-barrel intake manifold available. Might (or might not, don't know) be difficult to find.

 

If you can find one, definately would be easier to set up a set of quads than change the drive-train. And while three two-barrels are eye-candy, dual four-barrels WORK as well as eye-candy. Throw on a repro Ford (mill off the FoMoCo) air cleaner with the aluminum top (polish), and the 322 would look pretty snazzy!

 

Jon.

 

What cfm 4bbls for the 2x4bbl units?  Any thoughts on "improved" exhaust manifolding to compliment the additional airflow of the induction system? 

 

NTX5467

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Willis - I am not an "exhaust" guy, so will defer that question to others.

 

As to carburetor CFM, or more importantly carbuetor selection:

 

I don't have one of the Offenhauser (other companies may have also produced manifolds) to look at, but most for these earlier V-8's had the "square" (3 3/4 by 3 7/8 inch) footprint. So to build the unit without adapters (I truly hate adapters, they look hokey in my opinion); one needs to use the earlier (1952 ~ roughly 1956 4-barrels). As I tend to be lazy, starting with Buick carbs that are calibrated by engineers for Buick engines tends to require much less "dialing in" when placed in tandom on a Buick engine. Buick used, in alphabetic order, Carters, Rochesters, and Strombergs. Personally, I prefer the Carters, but then I have some advantages over most as I have the capability of custom machining metering rods. So for just about anyone else, I would suggest a MATCHED pair of 1952 OR 1953 OR 1954 Buick Strombergs. Run choke on both, idle on both, and solid linkage (many of the early factory dual quads used solid linkage).

 

The actual CFM rating was not published (and I have custody of the Stromberg prints), but a "guesstimate" would be maybe 375 ~ 400 each. Remember that CFM on multiple carb units is NOT additive - (2) 400's is probably closer to 625 or 650 than it is 800. A major benefit in dual quads, especially with solid linkage, is better average A/F ratio cylinder fill density because of more uniform manifold runner lengths.

 

And if additional performance is desired, maybe some exhaust mods and a slightly wilder camshaft would take advantage of the better carburetion.

 

Jon.

Edited by carbking (see edit history)

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I have to ask, is your 322 in good working order. The 401 and the 425 are great, but the 322 is very cool and might simplify things a bit. And once you get away from the torque tube you need a new rear end. This is the issue with buicks but also upside, they will always be unique.

Assuming you want to go open driveshaft, 200r4 is slightly smaller than a 700r4 and eliminates the tranny tunnel mods. The 400 tranny connected to the 401\425 does not have overdrive but eliminates the adaptor. I found the 63 to 66 Riviera has the complete drive train and rear end if you want to stay nailhead. You can use a 90's roadmaster or caddy frame as they have the same track width and wheelbase.

Just be aware, its a big project going open driveshaft.

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The main issue with "open driveshaft" is the rear suspension/rear axle locating mechanism and its interface with the existing frame.  It could well be THAT you could find a four-link (or five-link) system that would do the trick and still maintain the rear coil springs. 

 

There was a B-O-P case for the THM200-4R automatics.  Not just the Chevrolet bolt pattern.  IF you might find a 3-Gen Camaro/Firebird automatic (either the THM200 or THM700 family), it might well have the needed cast-in mountings for the "torque rod" they used on that platform of Camaro. Then you'd need to adapt the rear axle locating "rods" from the existing rear axle to the situation on the lh side of the Camaro tailshaft housing.  The Camaro rear axle has a place to bolt on the "torque rod", which then parallels the driveshaft to the rear of the transmission, where it mounts and is rubber-isolated to the rear of the transmission.  . . . . just thought of that!

 

IF the 3rd Gen Camaro/Firebird automatic trans and the existing Buick "rods" can be interfaced successfully, then the other main thing would be the driveshaft, which will need to be "built" anyway.  Of course, as an "upgrade", you could get one built from aluminum or . . . . on a wild chance, the length might be the same as one of the newer GM light-trucks, a composite driveshaft (saves rotational "weight" and all of that). REMEMBER . . . you saw it here first!

 

NTX5467 ​

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Thank you all for your replies. I apologize for not responding sooner. Trying to get my son off to his first year of college has taken a large amont of time and patience. I have decided to bite the bullet and purchased a rebuilt 66 GS 400 with dual quads and other goodies and a rebuilt TH 400 switch pitch transmission out of a 66 Electra to be married to a rebuit 65 Riviera rear-end. I will post pictures on the work as it progresses, starting sometime in October this year. I will probably part out my working 322 to recoup some of my costs and sell my dynaflow as is out right. The only thing I am dissapointed about is that it looks like headers are out of the question since I am still using the 56 chassis and manual steering. I have been told there is just no way to get the headers trafficed around those obstacles.

Mark

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