Pontiac 389 engine with a Impco 425 - high idle

[storm]

Pontiac engines (not the corporate, chevy, engine) like yours don't really like alot of advance. I had a 77 Bandit TA/6.6 and it was set fairly low. The higher the compression the less advance you want so I would be sticking near the OEM settings until you get some driving done and then start advancing more until you see no gains. I doubt you'll be getting any benefit from 18 degrees @1000rpm when stock is 6 degrees @ idle (what's idle on that now 750rpm?)

[Steptoe]

According to the specs u have.. in crank degrees
6 deg intial
16 to 20 degs cent all in about 2900
10 degs in the VA between about 6" and 15" vaccuum