This is the axle in my 69GS400. I know the rear end was replaced at one time and I'd like to bump up the gear ratio but not sure what ring and pinion to get. Its currently a 3.08 I believe (tire rotation to drive shaft rotation method). Any help would be appreciated
So a ring and pinion for a Pontiac 8.2 is what I'm looking for then. Is the year significant in this case?
Let Jim and/or Brian confirm this, but all you need is the BOP 8.2 gears. Those are easily available from Jegs or Summit. What ratio are you looking for? 3.08 is a great compromise gear set. The higher numerically you go, the better your acceleration, but the higher your RPM is on the highway. You can figure out RPM at speed with the following formula, 336/tire height X gear ratio X MPH = RPM Add 200 RPM for converter slip So for a car with stock tire height of 26.6 and a 3.42 gear at 60 MPH, 336/26.6 X 3.42 X 60 = 2592 + 200 = 2792 RPM
Thanks Larry. Looking for better acceleration without going too crazy. Was thinking 3.55. Waiting for Jim and/or Brian to confirm. Thanks Mike. Its been in the family since new.
These are the gear sets, https://www.summitracing.com/search/department/transmission-drivetrain/section/differential-rear-end-components/part-type/ring-and-pinion-gears/year/1966/make/pontiac/model/gto?N=differential-case-design-type:gm-8-2-in-bop-axle+ring-and-pinion-ratio:3-55-1 See which Brian and Jim recommend, or whether they can save you money with another choice.
Just looking to get a little better launch and since its hardly ever on the highway going from 3.08 to 3.55 isn't too drastic. Based on the formula Larry provided above its only about a 356 rpm increase at 60 mph.
336/26.6 X 3.55 X 60 = 2690 + 200 = 2890 336/26.6 X 3.08 X 60 = 2334 + 200 = 2534 Yup, about 356 RPM. You can always go the way I did. I added a Gear Vendors Overdrive. My final drive is about 2.77. 60 MPH is about 2300 RPM.
Have not heard of that before. Just looked it up. Looks like it basically converts the 3 spd tranny to 4 spd. Nice way to go but above my budget.
Yes, add on overdrive that is good to 1200 HP. It's above your budget now, but maybe not in the future. Start saving. You can also look around for a used one. They are nearly indestructible, and Gear Vendors customer service is awesome.
He can .... But nothing in the aftermarket for the mid series carrier No 2.93 no 3.08 no 3.23. 3.36 is a close as we can get to 3.23 in the aftermarket. Jim JD Race
