Idle drop by 500 rpm?

fishmens67 said

2.5 out? should be 1.5 max.
I think you should look for a vacuum leak.
Holley 750's are factory spec'd for 396 Chevy. if anything it would be rich for a mild 340.

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When I pulled the plugs, after pulling it from the ol 66 Sat, they were healthy grey...with points. It the carb I got when. I built the mill. Ported heads, oversize valves, 155 psi, full Grove mains, 8 qt pan ( never again, lol) ARP rod bolts, std bore TRW forged pistons, high volume oil pump, strip Dom, just a fun Lil mill, w/ reliable street ability...