I have a 1978 Delta 88 Royale coupe. Last year we took out the stock Rocket 350 and the Turbo 350 trans, replacing them with a built Olds 455 marine block with K-heads and a Turbo 400. The motor puts out about 400 HP and over 500 lb. ft. of torque. But, with the stock open differential and 2.41 gears, you can't feel the power coming off the line. I know the gearing was for MPG, but I don't care about that. I'm thinking of going with a posi and 3.42 gears. Are there options to swap in a used posi rear end (e.g., '95 Impala SS or same year Roadmaster)? Any other thoughts would be appreciated.

Thanks, Mike

 

Believe that rear end is the "corporate" 8.5 in unit. There should be an adequate selection of aftermarket ring and pinion sets available.

 

That 95 Impala used wheels with a 5" diameter bolt pattern, so you would have to have the axles redrilled and center machined down too.