X2 what fastback said.I would also look into a new t.convertor to match up with your gears and cam.Brian is the go to guy here.He will help get you started.I have a 408(410)and would build another,they,re torque monsters for a small block.Good luck.
I could change my converter and rear ratio till next week, but why?? - that cars main task is driving on the autobahm (80-110mph) and it should be good for some fun drag racing on weekends - 3 or 4 times a year
