How do I ID a 4 speed, overdrive or not?

fstfish66 said
the first gear ratio in that box is 3.09..with a 27/28 tall tire and 4.88 rear gear, you will neeed to hold on the the shifter before you floor it LOL.

the RPM is gonna come up very quick,,if you have room for a taller tire go with it,then you wont have to spend the bucks for another gear,,

i have a FORMULA S box in my barracuda,,,same first gear as yours 3.09

i have 4.56 rear gears and 33 inch tall tires,,but my 4th gear is a standard 1to 1 ,,the 33 inch tall tire and 4.56 work out to a final drive of 3.89..just shy of a 3.91..so at 60 on the high way my RPM is 2850,, not bad,, but an O.D is in the plans sooner or later,,,

the 4th in your box is a .68 reduction,,im guessing your RPM drops around 800/900 RPM,,???

find out how much it drops and then figure out where you want it at when cruising to determine your tire and rear gear ratio needs,,

Thanks for the input fstfish66. The Dusters gonna be mainly a street car so 28" tire is max without cutting the quarters. I'm sure I'm gonna have to be fast at shifting but it will only be for a little while till I can afford a used chunk. I may even look into a cheap one-legger and either swap in the sure grip or use the open then sell the whole 4.88 suregrip chunk to almost pay for another chunch with better gears.

I had 3.91's in my 68 Satellite with a 440/727 but I think that had 29-30"tires. But I has happy with its street maners.

Butch