rel3rd

iTrader: (43)

The calculators above in the STICKY seem to be fairly inaccurate.

My car has 3.42 gears, 25.66" tall Drag Radial tires, and traps at 5900 rpm's, according to datalogs.

I shift at 6700-6800, so I'd like to get the trap rpm's up near there as well.

From experience, does anyone know what rear gear I'd need to accomplish this, or that would be close?

I'm thinking 3.90's or whatever Motive sells that is right close to that? I think 410's MIGHT be too much with a short tire.

Anybody have any real world experience here, and not a link to an inaccurate online calculator?

ShiznityZ28

iTrader: (11)

3.73's would be roughly 500 rpm at the same mph and 3.9 ~750. but remember if your car gets threw the rpm's quicker you may pick up mph depends where the power is so 3.73 might be right especually if you plan on doing any other mods. now if your gona put a 28 on than 4.1 would be best.

my real vote is leave the 42's and spray it. that cam loves it.

rel3rd

iTrader: (43)

hahaha...yeah, I have been kicking that around now for a while...much moreso lately.

I didn't really want to mess with tire size, since these little 275/50's seem to work on my car...plus I have a spare pair already.

Peak HP on that place's dyno was at 6500, but if you recall it was still pulling at 6700, fwiw...

mrdragster1970

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On my cars I get ~300 RPM per gear. Auto's with big stalls.

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Z-RATED94

iTrader: (6)

Don't know if this helps any, or if I'm even quoting the right person. But I think it was Warren Johnson that said to add 5 percent from where you shift at, for the rpm you should see crossing the finish line.