Senior Tech Team
Join Date: Jun 2009
Location: Pittsburgh, Pa.
Re: Tune up specs for a 454...
This is with the stock 1978 HEI distributor. The engine has less then 15,000 miles..
I've disconnected the vacuum advance and rasied the initial from 12 to 22. It runs so much better!! It starts very easily when hot. But I still have all that mechanical advance, I think its around 20 fully advanced.. I didn't try full throttle but I'll bet it pings.
I'm thinking the mechanical in these HEIs put 20 in. So I'm going to have to limit the mechanical to 10-14ish..
It runs so much better mainly in the part throttle and just off idle..
What's the maximum advance without any vacuum advance you would run? This is a low compression 1978 454 factory stock. I switched the thermostat to 160 and have the under hood cleared pretty well. I removed that big HVAC box, compressor, etc. I am running a Champion 3 core rad with a 160 thermostat.
It runs pretty good but there always room for improvement.. It idles much better. Part throttle cruise without the vac advance is dead smooth with a nice mellow throaty tone. I no longer have to keep correcting the gas..