Change from 4-speed to 3w/OD

Marcohotrod said
Kelster-what is your rear gear and tire size? 3000 at 70 is no big deal. change oil + filter more. go to a taller rear tire. the 1:1 gear in an overdrive, call it whatever is strong-the same as all a833 units-I ran 12s with around 450 torque, and the overdrive gear is strong too. call it a 4 gear. my buddy, seaweed the junkmaster , sold me this unit cheap, all aluminum with an iron sidecover and iron front bearing retainer, we turned down the front bearing retainer to 4.80", easier than enlarging the bellhouse (if u have a 4.35" house-not so) and 27 spline output, 308 front bearing, and I banged on it for a few years no problemsView attachment 1715136855

Wow! I think I got more than I bargained for. I will copy all this info and share it with my mech. And thanks all of you for your participation
Bare with me I'm new at this. I think we should all agree that this is a 4-speed, if you want to say 3-peed plus OD that would be cool by me even if it ain't proper.
Rear gears 323, The back tire is much larger not sure the size, the issue is I want to go faster than 70 and I drive this car a lot and the speed limit where I drive 30 to 60 miles a day is 75 and you'll get runned over if your e not doing 80+, and I'd like to get better gas mileage
This is what I understand with out knowing all the science: 1st is shorter, second is longer, 4th is 1:1 but is now actually 3rd gear, the old third gear is now flipped around or something and is now the OD, I also understood this trans will bolt right up, shifter is the right place and everything.