My '57 235 starts and runs beautifully until I reach about half throttle. At that point, the power drops off slightly and stays flat until the pedal is on the floor. When I let up to about half throttle, I feel a slight surge. The initial acceleration is fine, it just starts to drop off about half throttle. This problem was noticed after I had done some repairs when trying to fix another problem: rebuilt carb,new vacuum advance(timing set ball to pointer,then octane selector at about 6-8 advanced),new fuel filter(generic type between gas tank and fuel pump. This was similar to but not exactly the same filter used previously),points set correctly (before timing).
Vacuum is 20. My inclination is that it is leaning out under heavier acceleration. Carb is a Rochester B. Accelerator pump is working.I soaked it in cleaner and blew out the passages with compressed air. I wonder if the problem is:
1. the carb
2. fuel filter is more restrictive
than previous one
3. something else
I'll bet one of you guys know. Thanks.
