Quote:
55panama wrote:I guess I got about three miles to the gallon. The car was running poorly, the carbs I was using were not the Caribbean carbs but old carbs I had laying around.
As you learned, the correct dual quad carbs are very different from the random single 4-bbl, but not 5X worse. You had junk carbs pouring raw fuel down the intake.
FWIW, I've used professionally rebuilt single 4-bbl carbs on a Caribbean intake and with a direct reading O2 meter seen them producing ideal air/fuel ratio at cruise.
Where the major difference is at idle and deceleration. The single 4-bbl has four idle passages. The correct dual 4-bbl carburetors plug the secondary idle passages, so the manifold sees only four, not eight idle passages. With all eight idle passages functioning, the air/fuel mixture will go dead rich on deceleration, wasting a lot of fuel.
Also, the procedure for adjusting idle is critical and there is a Rochester Technical Bulletin which shows step-by-step how to correctly adjust the idle.
As you probably know, the 1955 Caribbean carbs are quite different than the 1956 versions.
jack vines
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