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Gear ratio decision, 4.1 4.3 or 4.56?

1338 Views 24 Replies 12 Participants Last post by  PHWOARchild
Currently a blast to drive but I want to try dial in the whole system even more, wondering of the 373 are just too mellow for what this combo needs? sometimes at part throttle acceleration it seems a little sluggish.. id like more instant snap if that makes sense..

Currently have 373, and its nice, but i wan to push the street factor the the limit - the 383 doesnt always have the brute low end of the big bocks, so some mods are necessary.

Cam is around 2000-6000 236° / 242°, 288° / 294°, 11:1 (installed straight up), 200/64cc alu heads, 5.7 rods. 850 dbl pumper brawler, Vic JR, 1-3/4 LT headers into 3 inch collector and 2.5 true duals. 373 posi, 2004R, 3k stall..

18-20 initial, vac adv disconnected .. Hei stock.
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1979 Chevrolet Malibu 496-TH400-9" (cruiser). 1992 Chevrolet S10 355-700r4-7.625" (daily driver).
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18-20 initial, vac adv disconnected .. Hei stock.
Have you checked the total timing on this set up? Figuring out where it is at various RPM may provide some benefit.

When you have some free time do a google search on "recurving HEI distributor" and "limiting vacuum advance." It would take pages to explain the whole thing. What I can say is the way it is now can certainly be improved. I think getting the mechanical advance in a little earlier than the typically slow advance of the stock HEI and operating with an adjustable vacuum advance should be an improvement at part throttle and overall.
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