The Stovebolt Site Forums The Shop Area The HiPo Shop Question for Carb King- - - - -

Jon, I'm planning on building up a somewhat warmed-over GMC 270 to power a replica of a 1950s dirt track race car. It will have some fairly radical cylinder head, valve, and camshaft modifications for high RPM operation. I have acquired a couple of the 4-bolt 2 barrel carburetor footprint intake manifolds that were originally used on military GMCs. Can you recommend a suitable carburetor that will bolt to that manifold, one that can be tuned for high performance without having to rob a few banks? I've even considered machining an adapter plate to mount a Quadrajet, but I share your negative opinion on adapters. Thanks in advance!
Jerry

Jerry, assuming you are referring to the small footprint 4-bolt (same as a 265/283 Chevy)?

If so, a Stromberg WW is your cup of tea.

These were used on engines from 224 CID to 270 CID; so different venturii versions exist.

The WW idle jets, main jets, power valve, and power valve actuating valve are ALL removable / replaceable so tuning would not be a problem.

The only design "defect" of which I am aware is the aluminum throttle body. Virtually all Stromberg WW's require bushing the throttle body. Once bushed, issue solved.

Probably the least expensive of the WW would be the MoPar 318 carbs. Possibly a more desirable unit would be one from a GMC V-6 305 or 351, both of which have 1 3/16 inch venturii. The GMC version are manual and would have GMC linkage.

We have kits for any of them, plus a good selection of idle jets, main metering jets, and power valves; plus we make a actuator valve spring kit with various tension springs.

The GMC prefix stamped on the airhorn is 23.

I still don't understand why these are not used by more of the hot rod crowd, as they are more easily tuned than the Rochester 2G series. Probably because many of the hotrodders are familiar with the stock Rochesters, and have not looked at the Strombergs.

Jon

Sounds like a plan- - - - -I was considering the Bendix/Stromberg carb already. By the time I'm through tinkering, that "270" is going to be somewhere north of 300 cubic inches, with an overbore and a stroker crankshaft. I just happen to have one of those GMC 305 V6 carburetors on hand. I'm pretty sure Schneider Cams can come up with a suitable "race only" cam, as this one won't be seeing much, if any low RPM time. "Go fast- - - -turn left!" will be its primary mission! Thanks!

Edit: How would one of those carbs respond to a switch to a methanol/Hydrogen Peroxide fuel mix? My father ran 300+ cubic inch flathead Ford engines on that fuel back in the early 1950s. They had to run the carb dry between races to keep the 20% concentration Peroxide from eating the bottom of the float bowl. He was running a highly modified Zenith 2 barrel designed for a big Mack truck gas engine.
Jerry

The bowls are aluminum and would tolerate methanol if flushed with gasoline before shutdown.

If I remember correctly, H2O2 will destroy aluminum; I would not wish to use it with an aluminum carburetor.

If you are going to run that stuff, then maybe a Zenith 28ADA10 with cast iron bowl would suffice; however, you might wish to consult cousins Frank, Jesse, and Cole for financing options.

Jon

He rebuilt, or at least disassembled and cleaned the carb after every night's racing. That fuel mix was also known to eat the bottom out of a 5 gallon steel GI fuel can on a couple of occasions I'm aware of!
Jerry

Jerry, you have that GMC 351 V6 carb that may work. I think it's a trapazoid pattern though.

Yes, that one would need an adapter to fit the rectangular manifold footprint. It's going to be headed your way soon. I've got a couple of the MOPAR Stromberg/Bendix carbs for the 318 engines.
Jerry