Carb tuning and timing

[JayBar]

Well it all started when I pulled my distributer to prime the oil system, after installing an oil cooler. I lost the timing mark on the distributer. Cranking the engine the first time produced a few large back fires through the carb. I then retarded the spark and the car started. I played around with the timing and finaly got it (I thing) at 32 degrees of advance. Then the idle seemed to be higher than before so I turned it down a bit to 800-900rpm. At that speed it sounds great and shakes the car in the "badest way". Then I played with the 4 corner idle mixtures. BTW the carb is a HOlley HP 750. And I noticed a strange thing. No mater what I did to the mixture screws nothing happened to the idle speed. This was not the case when I first tuned the engine. I could stall the engine by not backing out the mixture screw fast enough. I also re-gaped the plugs at .50 they were .40.

Now when I drive along after the engine warmes up the car starts to pop out the exaust at a steady cruse. Not constant just now and then ,it is comming out of the right side only.

I am thinking several things. One I know the rotor and cap need replacing they are MDS. Then maybe the backfires through the carb blew out the power valves hence negating the function of the idle mixture screws (thought I don't know why). It there a way to check the power valves?

Engine 408, cam 336/348,112spacing,.575/.595. Edelbrock performer manifold.

Any suggustions?