Discussion in '1982-Present GM Diesel' started by 84CUCV, Apr 21, 2007.
it a 6.2 th400. Still not to sure how to figure out the rpms. thanks for the help
Well it depends what size tires you will run but with the th400 you can go taller gears so 3.73 should get your RPM's lower for better MPG.
That is assuming you had 4.56 beore since you have a M1008 CUCV right?
Or did you have a M1009 with 3.08?
i have both cucvs. i am taking the axles from a m1010 and taking the 3.73 3/4 ton and putting them into the M1010 and going to sell it i hope. will the 6.2 be able to hit 70mph ok? thanks
Assuming 31" tires it'll be doing about 2850 rpm at 70 mph. Not great, but doable. 2650 rpm if on 33's...
I have some 33s. thanks a lot
Speed x gear ratio x 336 divided by tire diameter will get you very close.
There's one calculator: http://www.phnet.fi/public/mika.jussilainen/laskuri2.htm
I was woried that I'm killing the engine with 4 speed box (I may have found SM465 dirt cheap) with 33" tires and 4.56's, but after some calculating rpm's are around 2320 when going 50 mph (that's as fast as I can go legally with 'Burban). Someday I get NV4500, but at least for now they are really rare in here.
Gear Ratio Calculator
mine will hit 70 but i have 456s, came stock with 3.73 (no lift) and she'd hit 70 on a good day.
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