I figured a torquey big bolck was going to HAVE to have more than a 10 bolt, I'm not sure whether to go with a 9-inch, or 12 bolt. the engine will be a 461. tranny will be a manual, hopefully a t-56 (for the road).

what if I find a 12 bolt out of a truck? how car is it to convert to the coil spring set up we have, from the leaf spring they have?

 

I would actually go with a 9-inch. I can hook you up on a deal for around $1000

 

You don't want a truck 12 bolt. The gears are different from a car 12 bolt and the diff is much too wide.

I ran a beefed up 10 bolt in my car. It ran as quick as 11.2 at 121 mph. I only converted to a 9" because my new tranny has a transbrake and I didn't think the 10 bolt could take the shock of the transbrake more than once. I doubt the manual transmission would do much good either.

Using a factory 12 bolt or 9" is going to give you problems if you intend to keep the torque arm suspension of the F-body. You can buy a mounting bracket to attach to a 9" housing but there's no easy way to mount the torque arm onto the cast iron housing of the 12 bolt.

All the aftermarket housings, 12 bolt or 9" are considered a bolt-in housing with all the proper mounting pads.

When I converted to a 9" I eliminated the torque arm and installed ladder bars.

A complete aftermarket 12 bolt or 9" including gears, axles, carrier etc, ready to bolt-in will cost you around $2000. Just add brakes.