Alright, i have an 85 cutlass, with a chevy 302 in it right now. i recemtly had a 350 in it but blew it up. Anyways i cant seem 2 get my timing right on my car.i have a stumble on hard acceliration. Right now i have 22 degrees of timing (acordding 2 the snap on light i have), i had the timing at 29 and the and the stunble went away. didnt ping, but when going 2 start the car it doesnt start right up. so i backed it down 2 22 and the starting was alittle better but the stunble started 2 come back. i had this problem in both of my motors and i dont know what 2 do? it seems when i advance it it gets better but the starting gets worse. the specs on the 302 is 12.5:1 comp. raiio, mild cam. 1.6 ratio roller rockers, aluminum heads flow 190cc, headers, exhaust, 670 holley carb, 110gph eldbrock fuel pump, rpm air gap intake, proform hei distributor. Any help or information would be greatly appreciated, thanks.
helppp
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what color race gas u using? ur cam has alot to do with it to, when u start getting to that compression. something about valve bleed off with big cams.i dont have alot of experience with it tho. and ur timing has a big part. was the cam degreed when installed or were the gears just lined up?
vp race fuel website has a chart that will tell u what octane gas u need for ur compr. and i would play with the timing a bit more. try setting at in the middle of 22 and 29 like around 25 or 26. on the only 12.5 compression engine i ever built we would run 5 gallons of 108 with some 93 pump gas and run it at 26 to 30degrees timing on a locked distributor. at the track we would put in all 108 octane and bump up timing to about 36to38 degress. and on nitrous i would put in 108 and drop timing back to 26degress.
I use 93 octain, my chevy 350 that I had before this was a 9:1 comp ratio and had the same problem.
22 sounds way too low for total advance, but a bit high for initial... how is your distributor set up... is the timing locked or does it still use a vacuum canister? Somewhere between 30-36º is probably a good ballpark for total advance.
Its a vacuum advance distributor, its 22 initial timing whith adance it goes up 2. 31 maybe., but if I raise it 2 say 26 the advance goes up but that's way 2 much timing
Is it aftermarket? You typically have 20º or more vacuum advance with a stock canister. If that's the case it could be why you're having issues... most SBCs don't see much more than 36º mechanical at WOT.
Yea its an aftermarket proform hei distributor, 50,000 volt coil, I should maybe swap a stock one in there and see what happens, maybe my vacuum canaster is not working.
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