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geezer#99 · 01-31-2018, 06:32 PM

At elevation you need to start the fire way earlier. You might find you’re up near 20 initial.
When I lived at 3800 feet I had a 396 like yours, I could run a locked in distributor with 30 degrees initial. Always started hot but I couldn’t run more than 10 degrees from the vac advance (at 2000 rpm) or I’d hear low rpm detonation. It was a beast of a motor. I drove it gently thru a 3ott too.
You need to experiment to find your optimal timing.

01-31-2018, 06:32 PM	#28
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,508	Re: 396 BB Question=Need advice At elevation you need to start the fire way earlier. You might find you’re up near 20 initial. When I lived at 3800 feet I had a 396 like yours, I could run a locked in distributor with 30 degrees initial. Always started hot but I couldn’t run more than 10 degrees from the vac advance (at 2000 rpm) or I’d hear low rpm detonation. It was a beast of a motor. I drove it gently thru a 3ott too. You need to experiment to find your optimal timing.