350 running poorly, flickering vacuum gauge
My brother and I are trying to tune my fathers 67 ss350 camaro. For the life of me, I cannot get this to rune right. the engine is a 355 with what we are told is a Comp 280 cam. It has an Edelbrock 750 carb and an HEI for which I have just replaced all components with no improvement. Plugs have a tannish dscoloration (no soot and appeasr normal). The engine does not smoke. There is no vacuum leak that I have found.
The car lacks power and also idles poorly. Interestingly, the car idles much better when it is advanced and it appears that it has appx 30 degrees of advance at idle when the vacuum advance is connected. When disconnected, it drops to 10 degrees and idles much poorer. The car lacks punch at higher speeds, esp 3 and 4 gear
A vacuum gauge shows appx 12mmHg at idle. The needle rapidly flickers up and down 1-2mm at idle. When RPM is increased to 2000rpm, the needle smoothes out. Also of interest, when I intoduce a vacuum leak, the needle smooths out and the engine idles much better
My next step is a compression check. What could be doing this? Where should I go next?