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Old 01-25-2012, 04:00 PM   #16
mud.man.rj
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Join Date: Dec 2011
Location: Creighton Sask. Canada
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Re: Vacuum advance issues

Quote:
Originally Posted by cppursell View Post
As I mentioned above, I conquered the 307 doggie-ness by using 283 power-pak heads, giving a higher 9.9:1 compression.

Yes I agree vacuum advance is valuable. This mechanic told me to just run without vacuum, and now after my research I wholeheartedly disagree with him.
The mechanic is right if it is an all out mostly race engine but not a street or part time srip engine, the vac advance is there for a reason, besides part throttle it helps a lot for economy because as stated you would be running it pretty retarded and then low power and kind of gutless. Start with heavy stock springs for initial advance then reconnect vac advance and readjust when driving, just make sure it is ported only not full vacumn that way it starts off with no vacumn adv until the throttle is just part way open then it helps as you accelerate so it is mech only until the throttle starts to open, if it was full vac then the advance would give extra timing at idle and cause ping not what you want as noticed.
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