Need rear end gear advice...

I have a '57 Chevy 1/2 ton...I'm planning on runnung a 472 caddy motor (some hop up work being done) with a th400 caddy trans... Been waffling on rear end gears... should I go with a 3.42? 3.08? OR???

I need some imput please...

Don't want to break the speed of sound but I don't want to top out at 70mph with the motor revving at 5000 rpm's either...

I plan on running 15" wheels in the rear if that matters at all...

Thanks,

Tim

 

That is all going to depend on the HEIGHT of the rear tires you run. I hade 3.42's on a car with 28" tall tires and it worked great!

 

Hex that Cad motor likes the low rpms.It makes it up with mountains of torque.Unless you have put a shaft rocker setup on it DONT even think about winding it up.The stock rocker train will fail.You will find 2.8 to 3.0 is a real good choice for the cad. It will still go like HELL, and get better gas milage than a bbc.I would recomend a 30" tire and 3.0 gears.With that gear and tire with a posie it will burn rubber for a block!---Feder

 

Best choice for a rear gear is to look what the Caddy had in it stock. The Cadillac is a fairly heavy car so your PU won't come close. As has been stated the Cad. makes a ton of torque, use it. I have a friend here that converts Pu's to Cad power regularly and he can't find gears that are low enough. The best combo he's put together so far was a 2.5 something rear and it worked super. I think if you look up what Caddy's come from the factory with it will be a real eyeopener. If you deviate much from a stock gear ratio you'll have a truck with its toungue hanging out before you reach 60MPH.

Frank