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Old 06-08-2017, 12:49 PM   #6
davepl
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Join Date: Aug 2006
Location: Redmond, WA
Posts: 6,334
Re: Initial timing specs for 1975 400 small block

I'm normally the guy yelling "Do whatever the factory did" but they likely had that thing super-retarded to keep the exhaust hot so that the AIR injection and new catalytic converters worked.

Unless you're feeling nostalgic, I'd aim for what runs best, maybe starting around 8 BTDC, to be honest...
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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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