Engine: Thinking about hopping up my ‘50 Champion flathead:

[David Conwill]

[PackardV8]

Yes, definitely, the 185" is the single most cost effective method of increasing Champion power.

A street Champion can't use 3x1-bbls. They'll work, just will use fuel and won't make any more horsepower than 2x2-bbls. FWIW, I've been hoping someone will try three motorcycle carbs. We did it thirty years ago and it worked great. The manifold is dead-simple, just three stubs on flanges. The good thing about most motorcycle carbs is they are vacuum operated and can't overcarburete; since you're rightly concerned about low speed drivability, this would answer that question.

Iskenderian still has the masters for every cam they ever made. Send them a core and get it back in two weeks for cheap.

As you mention, the duals are just for show and sound. They won't add any horsepower. A fabricated header looks cool, especially if you made long sweeping tubes and had them ceramic coated.


Yes, figure $100 each for custom forged pistons.

jack vines

[David Conwill]

Thanks Jack, good info. I should mention that I'm thinking of plugging the idle circuits on the secondary carburetors, which should mostly alleviate the excess fuel consumption. The flathead probably doesn't flow enough to take full advantage of all of the cfm potential of even the smaller secondaries, but I'd rather have the triples so that there isn't the terrible bog off the line that so many engines have when over carbureted - gotta keep that velocity up.

Maybe put the Stude carb on the shelf and run straight Willys carburetors, still too much potential cfm, but less of a problem at WOT.

[PackardV8]

FWIW, it's not just the idle circuits but also the accelerator pumps which are the main reason multiple carbs use so much more fuel.

Bog off the line is more driver than just CFM. An aware driver who leans into the throttle only as much as the engine can take won't bog multiple carbs. I'm running 2x4-bbls on my Packard V8 with straight linkage. Most everyone told me it wouldn't work without a progressive linkage, would bog and otherwise behave badly. They work perfectly; the only downside being the expense of two accelerator pumps and two idle circuits using twice as much fuel when the throttles are opened. The extra performance is worth every dollar.

jack vines

[David Conwill]

Of course, you're right, any time there are mechanical secondaries in play there is a risk of too much, too soon.

At the risk of getting off topic, I'm curious about your Packard V8 - are we talking about a 374 with two WCFBs? Those are very cool engines.

The thought of a Cadillac or Packard swap has crossed my mind with this car, but it's really clean and I don't want to mess with it a bunch (i.e. trans, rear axle, front suspension, better brakes, etc.). Plus the idea of getting more out of the original engine is appealing.

[PackardV8]

Of course, you're right, any time there are mechanical secondaries in play there is a risk of too much, too soon.

At the risk of getting off topic, I'm curious about your Packard V8 - are we talking about a 374 with two WCFBs? Those are very cool engines.

The thought of a Cadillac or Packard swap has crossed my mind with this car, but it's really clean and I don't want to mess with it a bunch (i.e. trans, rear axle, front suspension, better brakes, etc.). Plus the idea of getting more out of the original engine is appealing.

Packard and Cadillac 2x4-bbls used the Rochester 4Jets. Chevrolets and Mopar used 2x4-bbl Carter WCFBs. The later Chevrolets, Pontiacs, Mopar and Studebakers used 2x4-bbl Carter AFBs. A few late race-only Fords, GM and Mopar used 2x4-bbl Holleys.

jack vines

[LeoH]

Good luck Dave and keep us posted on what you do and how things work.