I finished restoring my 1950 Chevy convertible over 2 years ago, its completely original except for the engine, which is the factory 235 with a "street" cam, dual carburetion (stock Rochesters) and standard "solid" instead of hydraulic lifters.
The car has manual transmission and runs on 6V.

My great concern is the engine which was fully rebuilt but has so far NEVER run well at all! I 've done all I could myself, plus subsequently several friends, two mechanics, etc but still no improvement.

Compression reads ok, so does vacumm and all adjustments (points, plugs, valves, timing, etc) are right, although I have tried various different settings too but without any improvement.

The engine idles rough, like 1 or 2 cylinders are not firing. As it revs up the feeling is the same. It pulls with a few slight flat spots as the revs go up but falls short of breath well before the "imaginary red-line" (I don't have a tach on it, but it feels like power drops off some 800 rpm short at the top end.)

I also have a 53 Chevy, manual and with a standard 235 (only one carb, etc) and it is appreciably faster than the conv and inmensely smoother, both having the same rear ends (3.55:1).

Naturally, in this very long time I have done all that might come to mind several times...even had the head off 3 times to recheck valves, springs; carbs out for recleaning and adjusting. etc, etc. Have tried several different plugs, points, condensers and so on, even different carbs.

I wonder if somebody out there has some ideas as I reckon there still might be something we have missed to get right...although this is a relatively simple engine, but still.....

All suggestions most welcome as the engine has driven me nuts by now and I am losing the battle!

Many thanks!

Lars S.

did you downsize your carbs to fit your engine?If you are putting twice the fuel and air as one carb it will not run right.I tried the same set up back in the fiftys on my fifty chev.Was more bother than good.duel carbs have to be balanced to idle good.[same vacuum on both carbs]A small four barrel would work better but not near the eye appeal.

Thanks for the comments, Chevysix.
Yes, I did downsize the carbs (went through a long trial & error process by the way)...cannot recall what size jets I settled on but quite sure they are suitable.

Anything else I might have skipped?

Aghree a small fuar barrel woulod probably be better but plan to have these duals work for their livvi9ng.

Thanks!
Lars S

Hook a vaccuum guage to your intake and run it into your dash, take running readings and do the same with your other car and compare notes.if the readings are low on the dual carbs then you are drawing more air than it can handle.That is the same as putting a 750cu.carb on a 65 v8 you get great bogging and a lot of lag.

Thanks Chevysix.

Good idea, will try that!!

Lars S.