Okay at 60mph I'm at about 2700rpm is that right?

:snoozer:

I forget,what trans, gears, tire height?

255/60R15
TH350C
gears????

Okay at 60mph I'm at about 2700rpm is that right?

:snoozer:


The rpm depends on 2 things. Tire diameter and rear axle ratio.

255/60R15
TH350C
gears????
rear axle ratio... Th350, no OD...my old goodyear 255/60 tires were 25 1/2 in. tall if you know what axle ratio you have , Toobroke can do the math for you . tell you exactly how fast you are going at given rpm

The rpm depends on 2 things. Tire diameter and rear axle ratio.
and one more..whether you have Overdrive or not.

wallaceracing.com go to automotive calculators, should be able to figure out the gear ratio if the speed is right, if you know the gear ratio's of the differential and final drive on the trany & tire diameter you can figure out the speed for any given rpm. hope this helps.

I think I'm mainly trying to find out what the gear ratio is. Or about what the gear ratio might be. If it is all stock it seems kinda high for me which maked me think it has aftermarket/taller gears.

TH350 doesn't have over drive ( at least I don't think)

I think I'm mainly trying to find out what the gear ratio is. Or about what the gear ratio might be. If it is all stock it seems kinda high for me which maked me think it has aftermarket/taller gears.

TH350 doesn't have over drive ( at least I don't think)


Jack up the rear end and turn your tires one revolution. And count the number of turns your drive shaft makes. The number of turns is your axle ratio.

My '68 has a 350 HP 327 with the original tranny. At 60 in 4th gear its turning about 2,500 RPM. Your sounds about right if you've got a small block. If you've got a 427 or 454, that may be a bit high.

the small blocks were available with several gear ratio s , 3.08 , 3.36, 3.55 and more not to mention whats been done to them over the years by previous owners... do as toobroke said ..rotate tire and count driveshaft revolutions .. then you ll know

the small blocks were available with several gear ratio s , 3.08 , 3.36, 3.55 and more not to mention whats been done to them over the years by previous owners... do as toobroke said ..rotate tire and count driveshaft revolutions .. then you ll know


Yeah, it'll only take you 5 minutes to find out which ratio you have.

I just need to find the time is all.
Thanks guys!!