CarburetorsCarb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.
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I' m sure this posted some where but I could not find it. Late 80's roller 350, vorted heads, hei ignition, no computer, what is the timing spec?? I have it timed like a 70's 350 if I remember correctly and am now wondering if my carb issues are really timing issues.
Quite often "carb" problems are actually ignition problems.
Vortec heads don't need quite as much advance as older SBC heads. 32 degrees total mechanical is usually all that's needed, vs. the 36 of the older heads.
Initial timing should be in the 8-12 range. And, you should have the vacuum advance hooked up.
I'm running 30-32 degrees of total timing. 10 degrees base.
Also running with the vacc pod on the distributor and both ports on my Double Pumper plugged. seemed to advance too much otherwise.
Also found with the Vortec heads a slightly hotter plug (Autolite 26's) did better after 1000 miles of mixed driving, then the Autolite 24's I had on there with traditional SBC iron heads.
with my vortec setup i discovered that it needs alot of initial timing and only 32-34 total. i run 15 base timing with 33 total all in by 3000rpms and it seems to be happiest
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08 best: 13.07@107 on street tires, untuned