[geeteeohguy]

I changed the 3.55 gears in my '65 GTO with an M-20 to 3.36 gears. Made a huge difference. Put the car at 3000 rpm at 70 mph. This with stock 26.5" diameter tires. Recently, I went to 27.5" tires (15" wheels) and the rpm is now about 2800 rpm at 70 mph....equivalent to a 3.23 rear ratio. I've run 3.55's and 3.90's in early stick shift GTO's, and they were much more do-able when our speed limit was 55mph. Today, they are terrible choices IMO for a street car, especially with a 455 engine. 3.36 gears with a taller tire would be just fine in your case. Or, 3.08's with a stock-ish tire diameter. With a 455's torque, you'll be fine. Even with the M-21, if that's what you have. A lot of it is driving technique. I've had the same clutch in my '65 since 1984, and my 200,000+ mile Toyota 4Runner is still running its original clutch. A good friend has a '65 Ford Galaxie with a 4 speed and a 2.75 rear gear, and his clutch does fine, too. A lot of it is how you drive.

[Nutts]

http://www.summitracing.com/parts/rmg-4900111

Suggests I can get a 3.08 gear on a 8.2" 10bolt, whereas I thought 3.36 was lowest. Any thoughts on whether this is correct? Am I missing something or will this fit?

It is confirmed I have an M20 2.56 first gear after rotating engine at crank with plugs out and counting shaft rotations :-)

[geeteeohguy]

You don't have a 3 series carrier, as Summit says the gears fit. 8.2 ten bolt. Didn't you have a Chevy 12 bolt in your car? With 3.73 gears?

[Nutts]

I have a 65 Chevelle 8.2" 10 bolt, with 3.73 gears. I don't know what carrier I have right now.

['ol Pinion head]

Originally Posted by Nutts

http://www.summitracing.com/parts/rmg-4900111

Suggests I can get a 3.08 gear on a 8.2" 10bolt, whereas I thought 3.36 was lowest. Any thoughts on whether this is correct? Am I missing something or will this fit?

It is confirmed I have an M20 2.56 first gear after rotating engine at crank with plugs out and counting shaft rotations :-)

reread post#6

Have built numerous of the 8.2 Chevy rears, not much demand, but occasionally. Currently, have a nice set of Chevy 3.36's & '66 Nova housing in the racks. Once I stumble on smoking deal on a new Eaton carrier I'll assemble it, order new axles, & offer it for sale. For a cruiser/driver early Nova such a rear should hold up, for anything performance wise, not that good. Usually the '66 Nova guys want a 12 bolt. Real deal early Nova 12 bolt housings are very expensive. Some Nova guys will settle for a 9", been there, done that too.

[Nutts]

Update: 3.08 gears fitted in my 8.2" 10bolt carrier well by Liberty Garage Services in Uk. Car runs well - far smoother, quieter, economical, less jumpy, 70mph at 3000rpm.