I have done some testing (not on Chevrolet, but other makes on this subject), and the subject has been beat to death.
But:
(A) If I were really interested in this subject
(B) Independently wealthy
(C) Had an infinite amount of time on my hands
I would proceed in this manner.:
(A) Rebuild the original Rochester (need a baseline) and yes, I CAN rebuild these things, just don't like to rebuild them, and rebuild them, and rebuild them and...........
(B) Acquire and rebuild either a Zenith or Stromberg carb of the correct venturi size for the engine (better efficiency).
(C) Acquire an original Chevrolet single barrel intake and spare cylinder head.
(D) Do some homework on FACTORY inline 6 cylinder two-barrel applications, at first blush, the 232 A.M.C. looks promising.
(E) Once a suitable donor (eg. the AMC) was determined, acquire an intake for this engine.
(F) Bolt the original Chevrolet intake to the Chevrolet head, and cut out the entire plenum assembly
(G) Remove the plenum assembly from the donor, cut the Chevrolet runners to fit the donor plenum.
(H) Take the whole thing to a welder (my welding looks like the underside of my desk in the 3rd grade!!!
)
(I) Rebuild the Carter WCD from the AMC (another reason the AMC looks promising) with a calibration 2 sizes richer than stock.
(J) Fabricate a second set of rods which are only one size rich.
(K) Make an appointment with a dyno operator and test it all.
GUESSES, based on testing on other engines:
Original Rochester - 100 percent
Stromberg or Zenith - 110 percent
Two barrel Carter ON MODIFIED TWO BARREL MANIFOLD (after final calibration on dyno) - 115 percent
Two barrel Carter (or any other two barrel of your choice) on original single barrel manifold with two into one adapter - 65 percent.
The only way you will know for sure is to test it.
Jon.
