I have had the car on the street now for 4 years. I have had no problems. this past summer it started having some black smoke come out when i started it. it progressively got worse and eventually fouled out the plugs. I thought that maybe the plugs were just old and bought hotter delco plugs. went from 43s to 44s. I am still having this problem and its worse than ever. When you start the car cold thick black wet exhaust comes out and stains the drive way.

The car is a 86 trans am. I have done a engine swap. I have a GM ZZ4 350. The carb was built by a local carb guy and like i said i had no problems for years. the carb is a Holly 650 without a choke and vacuum secondaries.

I have read that it could be in the carb and i have also read that it could be in the timeing. neither have been touched for the car to progressivly get worse. the only work done to the car was i put new rocker arms on. Could the valve be out of adjustment and causeing this problem?

Please anyone....help!

I would just start from square one on holley tuning. Hook up a vacum gauge and follow sofaking's sticky thread in this forum. Set your idle enrichment, idle speed, timing. May need carb work since it's been progressive. They tend to build up with crap over time and plug air bleeds up.