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Old 10-27-2010, 07:43 AM   #19 (permalink)
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Originally Posted by Toby View Post
I agree that the options are very limited, and the c151 offers a minor improvement. Can you comment on the feasibility of the c141 diff in the c151 trans? I have been researching this combination but I can't find a final word on these internets. My understanding right now is that the c141 diff offers a better ratio and will probably fit. Do you know?
The C141 does offer a lower differential ratio 3.5 vs 3.7 I believe. However, you can not swap them out. The differential gear is removable, but the gear on the shaft is cut into the shaft, and you can't use a 4 speed shaft on a 5 speed transmission.

I really think that taking a donor trans, swapping out the 2nd gear and using it in reverse as a new 5th gear in a C151 is the best way to go. That would give you ~1600 rpm @ 55 mph which is pretty good IMO. Of course, this requires a fair amount of custom work and if you don't have access to machinery that means $$$.

I also messed up on my earlier calculations. The C141 puts you a 2500 rpm @ 55 mph, and the C151 puts you at 2200 rpm @ 55 mph. So, 1600 rpm looks even better.
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