Pontiac 389 engine with a Impco 425 - high idle

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storm
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Re: Pontiac 389 engine with a Impco 425 - high idle

Post by storm » Tue Apr 01, 2014 10:08 pm

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?)
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Steptoe
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Re: Pontiac 389 engine with a Impco 425 - high idle

Post by Steptoe » Wed Apr 02, 2014 12:38 am

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
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