Technical 3 Deuce SBC Speedway Setup?

Starting with genuine Rochester tripower carbs makes life a LOT easier than trying to make other stuff work!

Of course, dual quads are much superior to the tripower but if one is going to put tripower on a Chevy 350, carbs from a factory 348 Chevy are a great starting point!

But WAIT! 348 tripower carbs are EXPENSIVE!

True, but J-2 Oldsmobile carbs are not expensive.

Rochester used the EXACT same blank body castings (throttle body, bowl, and airhorn) on the 1958 Cadillac, 1958 Chevrolet, 1957 and 1958 Oldsmobile, and 1957 and 1958 Pontiac.

Yes, there are some MINOR machining differences (mostly what thread vacuum port is in the back of the throttle body), and the 1957 carbs have a different throttle return spring on the front and rear carbs than the 1958's.

So, for use as aftermarket on a 350/400 Chevrolet, one needs to remove the Oldsmobile arm on the center carb, and replace it with a Chevrolet arm; and a jetting change for the tune of the 350/400. How difficult is that???

For the show car dudes, the preceding paragraph is correct to convert to 1957 Pontiac. For any of the 1958 units, one needs to remove the screw in spring stud, and install a headless plug (from memory 10x32, but measure if you do this), and drill a hole in the throttle body on the passenger side to accomodate the 1958 throttle return springs. 99 percent of the judges would not spot the difference.

I can do it in less time than it took to type this post

As far as using 97's: 3 97's work fairly well on a 239 CID Ford engine. Are you Chevy dudes going to tell me that the "vastly superior to a flathead Ford" 350 Chevy engine doesn't require more air? Or maybe the flathead actually breathes better than a 350 Chevy

Jon

 

The Edelbrock 3x2 intake you need is a C357, if you're sticking with Edelbrock.

On another note, why can't you idle on all 3 Rochester carbs ???
I idle on both carbs of my 2x4 setups, can't be that much of a difference.
Say you still run progressive linkage, turn idle speed down on the outboard carbs, that way you always have fresh gas flowing through the outboards.