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#1 |
Registered User
Join Date: Jul 2010
Location: Tacoma, WA........Ottawa, IL
Posts: 69
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timing, backfire help
i have a 454 bored over 30 with flat tappet cam in my pickup, i just put on a holley 750 dp and an edelbrock air gap intake. i got the holley tuned to how i want it using a vaccuum guage, but everytime i get on the highway and get over say 3000 rpm or so, when i let off the gas im gettin a backfire, so i went and put on an advance curve timing kit and an msd super coil and rotor on the distributor, and i am still getting the backfire. ive had the timing down to 10 and as high as 18 if i put the timing up round 20 i get a fireball coming out of the carb, changed the spark plugs because looked like they were foul, was runnin pretty rich might still be runnin rich but im gonna give it a week or so to check the plugs and see if its still runnin rich. the truck runs great gets up and goes i just cant get rid of that backfire, if im only driving through town, and keeping it below 2500 rpm there is no problem. can anybody please help me out?
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#2 |
Registered User
Join Date: Jun 2010
Location: Upland Ca
Posts: 4,143
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Re: timing, backfire help
Kinda sounds like an exhaust leak burning off excess fuel.
__________________
1972 C10 SWB, Air, PS, PB, 350/350THM. Second owner. 1965 Corvette roadster, 44K miles, 327/365 SHP, 4 speed, side exhaust, knockoffs, teak, second owner (bought in 1970), Have ALL numbers matching components. My frame off restoration thread: http://67-72chevytrucks.com/vboard/s...d.php?t=556703 |
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