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Old 04-23-2018, 10:46 AM   #15
davepl
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Join Date: Aug 2006
Location: Redmond, WA
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Re: Big Block - possible timing issue (?)

Quote:
Originally Posted by geezer#99 View Post
Follow that link and become a pro.
I had a 396 years ago. Ran the timing locked out at 26 degrees, with vac adding another 16. Always started hot, never pinged, hauled butt, would chirp the hides into high gear. That motor liked lots of timing.
Good choice of carb.
Just had a 427 on the engine dyno, stock everything. Turns out it made the exact same power with 31, 32, and 34 degrees (well, within 2-3 repeatable anyway). I was surprised.

Down low they idle better and make more vacuum, but big blocks don't actually appear to like that much timing. That might change if you go open port to closed port, which changes the burn (mine's the old 1969 427/390).
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1970 GMC Sierra Grande Custom Camper - Built, not Bought
1969 Pontiac 2+2 427/390 4-speed Coupe
1969 Pontiac 2+2 427/390 4-speed Convertible
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