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rear end gears

1K views 2 replies 3 participants last post by  bonuts 
#1 ·
I have a 1986 chevy s-10 with a 350 V8 in it. We origionally put a TH700R4 tansmission in it and it went out. The automatic just wasn't winding out as tight as i wanted it to off the line when it was shifting, so bought a muncie M20 4-speed. I know i need to change the rear end gears because of the 1.00 4th gears ratio in the 4-speed.I was wondering what the best gears to put in the rear end?
 
#2 ·
For street performance, I like 3.73 gears, 4.10's if you do more racing than street driving. Either of these ratio's may be to deep for you if you like topend m.p.h. though! What gears are in the truck now? Go ahead and try the four speed with your gears to get a good indication of how much deeper you want to go. But, beware that the 7.5" rearend isn't very strong. 4 speed power shifts and sticky tires coupled with a healty smallblock could spell disaster for this rearend! If you are on a limited budget, you might try to find a later model S10 rearend in a salvage yard. Any S10 with a factory 4.3 engine or any 92' or later will have the 7.65" rearend with the larger 28 spline axles. If you are lucky you just might find a late rear with a posi unit and the gear ratio that you need in a neat package! Maybe under $200 ? Good Luck! :D
 
#3 ·
I ran a 4:10 posi for the first two years my S-10 got the small block treatment, I just found it to hard on fuel, and the back tires would bust loose too quick (that won't change unless I tub it... not likely). My S-10 also sees a lot of highway miles during the summer driving to shows, and just any spare time, so I got a 3:08 rear for mileage, not so quick but good on the highway. I'll be in the same dilema this summer when I swap out the TH350, for a 700R4.
out,


bonuts
 
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