Quote:
Originally Posted by Wbulk
Rick, I have have not bought the gears yet but was thinking of the 3.50s, not based on overdrive fifth gear that is .68 to 1, but on 4th, that is 1-1.
With 3.5 at 60 mph 4th is 2713 rpms and 5th is 1844 rpms.
With 3.73 at 60mph 4th is 2892 rpms and 5th is 1966 rpms.
I believe that's right based on the calculation program I used.
I wasn't considering the overdrive factor as the basis for the math. I felt dropping it down to 4th was fine when the power was needed. Looking at the numbers again I may go with the 3.73s.
Wayne
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Wayne it depends on the cam your going to run. I have a 1:1 4th and 0.63 5th with 3.5 rear ratio. My engine doesn't smooth out until about 1800 rpm (cam is 236/242 duration Think 108 SLA). It's a 5.0 stroked to 347 cid. The pipes are too loud at 2600 rpm and it lugs too bad in 5th. Honestly this combo sucks in my opinion. I will eventually change it to a 0.8'ish ratio for 5th. A milder cam would help, but the huge step in 5th I do not like. If you get the chance, go with a higher ratio 5th gear. You won't be sorry.
With a mild engine I would go lower in the rear - 3.73 would be the highest I would consider.