It will be cheaper and easier in the long run to put an automatic in there. Either a 727 or something else if you want more gears. Any manual transmission that is going to survive in a heavy car with a bunch of power is going to cost a bunch of money and take a bunch of time. You can build a heavy duty 727 with billet parts and a good converter for $4000 and it will bolt in. If you pick the right converter you'll also be able to drive it on the street as well as make nice solid passes at the track. You'll spend twice that much money for a complete manual, shifter, clutch, bellhousing setup and you'll need to have a chassis shop build a new tunnel in the car for everything to fit.

I just went thru this whole exercise with a customer who dropped a 700 hp 505 inch big block into his B body with a 23 spline transmission. Now he is having a 727 built with billet drum, manual valve body, pro street type torque converter, etc.