Whats up people, I'm new here and its good to be in the company of olds lovers. I have a 78 olds cutlass, I replaced the 3.8 litre with a 72 350 olds. The engine has .30 over forged speed pro flat tops,small performance cam, holley street dominator intake w/elelbrock 600, and 350 trans w/shift kit. Can anyone tell me what gear ratio is in this car? I want an 8.5 posi rear end with 342 gear ratio. Any ideas on what cars I can find a unit like this under and will easily interchange with my car?

 

There is no cheap solution. The only 8.5 axles that bolt in to the 78-88 A/G body cars were under the 84 H/O and the 85-87 442 and Buick GN. Good luck finding one that isn't made of solid gold. People have installed 68-72 A-body axles but the width is wrong and the suspension arms don't line up. Aftermarket adjustable arms are a bandaid at best. Others have had success with the Ford () 8.8 axle, but again aftermarket arms are required.