I would like to get a little more power from my 1987 olds cutlass supreme 307.Before I go to a 350 I want to try new rear gears first. Maybe 3.73. Will this give me a little better acceleration and where might I find gears to fit my car. Also did the 1987 442 have 3.73 gears and would they fit my cutlass. thanks for any advice.

 

Yes, the 85-87 442s came with 3.73:1 gears. Unfortunately, they also came with a stronger 8.5" rear axle (yours should be 7.5"). You can swap the entire axle housing, but not just the gears. Unfortunately, these 8.5" axles for G-body cars were only used in the 84 H/O, 85-87 442s, and 85-87 GNs. They are highly sought after and usually priced accordingly if you can find one.

On the other hand, the S-10 trucks and third and fourth gen F-body cars also use the 7.5" axle. If you're looking for wrecking yard parts, you can swap the gears and even a limited slip carrier into your axle housing. Just be sure to check for the proper spline count on the axle shafts.

 

Keep in mind the new axle gears will make your speedo inaccurate. You'll need to change the speedometer gears in your trans too.

 

I just realized you are from New Jersey. That means the axle swap your looking to do with 442 / GN / or SS monte parts is pretty easy. A lot of those cars cars are getting parted around here because of rust issues. I see the axles from time to time and they are expensive (but less than the 68-72 A-body size). I guess it depends on your perspective.