Thread: Need help
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Old 04-29-2015, 11:52 AM
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AKCJ AKCJ is offline
Join Date: Feb 2010
Posts: 4

Krash - I agree with Cory on plugging the vacuum advance until you get the other issues worked out. I've run with mine plugged for a long period of time with no ill effects except not so good highway gas mileage. I have a friend who went Howell FI on his 258 and it works very well.

Cory - thanks for posting the manifesto on vacuum timing advance. My odd fire 225 Buick V6 runs ported vacuum (well, it would if I didn't have it plugged). I've researched it quite a bit but have not seen it explained quite the way that you did. Vacuum advance at low engine load/highway cruising is pretty straightforward and makes perfect sense to me. I don't quite get the need for advance at idle - I guess I've assumed that the mixture needed to be rich at idle (like at starting) so you would not want the vacuum advance at idle. So, ported vacuum would be best. Apparently I was wrong about that. I did find out that there is a very large selection of vacuum advance canisters for the HEI distributor. You can take your pick on the amount of advance and the amount of vacuum to pull it all in.
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