Thread: Looking for another opinion. What is causing my backfireing.

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Originally Posted by HDSBC

Timing is set to 12 degrees

What is TOTAL timing (timing at 3500-4000rpm, with vacuum advance disconnected)

Originally Posted by HDSBC

Carb has 11 inches of murcury max at 600rpm idel

JMHO, vacuum is low

Originally Posted by HDSBC

the plugs are still black and some wet. And I have a dead spot from 2000-2500rpm where it backfires out the exhaust almost constantly and even will ocationaly stall and refire under light accelerations at slow speeds. It seams to run fine before 2000rpm and after 2500 it stops back fireing but feels as if it had a miss in a random cylinder every once in a while.

Classic signs of too rich. Check the power valve

JMHO, 1981 SBC truck motor had 8-1 compression which may not match well with your cam and head combo, requiring some serious tuning.