Packard Forum Index » Modification Discussion

I have always felt the Paxton supercharger should work well with a flathead engine because they have a low compression ratio, and the design is biased towards low speed torque. So you have plenty of punch at low speeds and the supercharger keeps it from running out of breath at medium to high speeds.

A stock McCulloch supercharger only puts out 4 or 5 PSI which is not enough to hurt a stock motor. It was designed in the early fifties to be used on the typical flathead of that time, in fact the prototypes were tested on V8 Ford flatheads.

If you are rebuilding the engine hardened valves and valve seats on the exhaust side may be a good idea on general principles but not just because of the blower.

VS57.com is the best web site on McCullochs, here is their history of the McCulloch supercharger.

vs57.y-block.info/history.htm

The easiest and all around best installation would be a SN or short nose type Paxton with a modern flat belt drive. But the most nostalgic or period correct to the early fifties, would be the VS57 with Vbelt variable speed drive even though it is more complicated.

For an air box how about a pressure cooker suitably modified? You can pick them up at yard sales and thrift stores for a few $$$ bux and the aluminum should polish up beautifully.

Packard did test a few VS57 installations in 1953 and 54 on their straight eights. I have seen under hood pictures of sedans in a Packard history book. I suppose they dropped the idea because the new V8 made it unnecessary.

FWIW, an air box is a waste of effort. If you use current high pressure centrifugal race engines as a model, none of them use a pressure box. The supercharger goes straight into a hat on the air horn of the 4-bbl carburetor. They run 15-30 PSI with no problems. A McCulloch would never see more than 5-7 PSI max.

jack vines

Old pictures of the first McCulloch blowers on Ford flatheads show an L shaped rubber hose clamped on the top of the carburetor. Later they made the air box, still later they went to the carb bonnet. You do not need the air box if you can seal up the carburetor throttle shaft choke shaft and float bowl vent.

Thanks to everyone who has joined the discussion. Jack, I have read a few of your posts and you sound like you know what you are doing around a Packard engine. As far as using an airbox, other than the Panther nostalgia angle, it is usually easier to seal a box than a carb- if you look at what Studebaker did with the R2 & R3 engines, when money was no object, Granatelli built the R3s with airboxes, while Studebaker built the R2s with hats & pressurized carbs. Both ideas work, but according to supercharged Stude guru Ted Harbit (the "Chicken Hawk" guy), keeping the pressurized carbs together requires constant maintenance. I was planning on using the stock carb- I think it is a WCFB, have to look.

I would also like to hear from the group about the use of the stock 359 aluminum head if it is salvageable. I have looked at some forum strings discussing the different combustion shamber shapes Packard tried, and would be interested in how they perform. It looks like the biggest performance change you can make is simply to separate the intake & exhaust manifolds, and do some simple intake porting or at least polishing/cleanup. The McCulloch should take care of the rest!

I forgot to add, I like the idea about a pressure cooker! Right now I am working on a R3 Stude airbox, but I think that idea could be really interesting.

Fuel injection should solve a host of carburetor problems if you don't mind fuel injection.

I've done them with air boxes and with hats. Knowing what I know now, I wouldn't run an airbox if someone gave me one. I just sold the last LS repro R3 box I had to a street rodder in Sweden.Quote: Ted was running dual Paxtons at 15# boost and later dual turbos at even higher boost. Your street Paxton on a straight eight Packard will never see even five pounds of boost. Absolutely no problem sealing a carb at that boost level.

Your car, your money, your decision.

Jack Vines

As one who has also been involved in blow-thru carb turbo setups for over 30 years, I also like the "hat" solution rather than the "airbox" setup. See:

originalho.com/TurboForce.html

There are aerodynamic issues with both arrangements, but the "hat" is particularly sensitive to aero configuration.

I agree with Jack that at 5psi or less, the carb maintenance is no big deal. At above 10psi, that changes though.

Craig

Any comments on EFI vs carbs? Seems to me the EFI would be easier and better than carb if you had an infinitely adjustable or programmable setup like Megasquirt.