Re: Holley Tuning
Idling rough = low timing.
As you increase the timing as mentioned, just decrease your fast idle screw to keep the rpm about 800+ ish. You'll need to set the idle mixture next.
Turn your car off and measure how many 1/2 turns it takes to wind each mixture screw right in (gently). Wind them back out to roughly the same spot, but make sure they are identical. The best way to set these it to obtain max vacuum at idle, but without a gauge just wind them in 1/8th turn each after you car is idling at normal temp (if you screw one, you screw the other). The rpm should increase very slightly as the mixture leans out. Keep doing this until it stops rising then wind it back out about 1/4 to 1/2 turn. This should get you into the ball park.
Normally black smoke = too rich. But if its jetted for a 302, then there sounds like other issues??
393 Tremec TKO 9"