351c 4spd
#1
My Mach1 has a 351 cj rebuilt with flat top pistons hotter than stock cam also eldlebrock performer intake and carb. probably about 380-390 h.p. at the fly wheel. What are the "ideal" shift points (R.P.m) with my 3.7.5./1 rear eand and toploader 4 speed? Wow
thanks Keith
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#2
Just before you feel the power drop off. I would use 3rd gear as it's pulling real hard in 3rd. 2nd is a little low, you won't be putting enough strain on it. Set your rpm roughly 300 to 400 RPM below where you can feel it drop power, and you should be close. Because the peak power is dropping long before you can actually feel it. JTS 71 Mach1
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#3
Although I am not an expert on shift point by any means, I know the 351 motor can handle high (6000-6500) RPMs.

From a non-technical point of view, I follow the animal theory for determining shift points. Basically, I like to shift into 2nd at the point the tires will squeal like a pig and 3rd when they will chirp like a bird!! 578254

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#4
(08-31-2012, 01:34 AM)JTS71 Mach1 Wrote: Just before you feel the power drop off. I would use 3rd gear as it's pulling real hard in 3rd. 2nd is a little low, you won't be putting enough strain on it. Set your rpm roughly 300 to 400 RPM below where you can feel it drop power, and you should be close. Because the peak power is dropping long before you can actually feel it. JTS 71 Mach1

You're right about it starting to really pull in 3rd gear. First gear is almost too low, I can easily start from a dead stop in 2nd, By the way I'm running a 373:1 traction-loc.
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