In the past few weeks I have been packing to move and every time I go to the garage I think I should add a little bracing to the frame. I am planning for the 496 I build to have right at or a little more than 600tq. I am needing some feedback on this issue to ease my mind. I am just afraid to start on the motor/tranny/exhaust if I need some added strength.

As long as your frame is in good shape, you should be fine. I've seen a few guys run some wild motors on stock frames with no issues. However, if you have the body off the frame at the moment...it might give you some piece of mind to check all the factory welds and make sure they all in tact, or grind re-weld where necessary. while I'm not certain its necessary, certainly couldn't hurt to slightly reinfoce the lower control arm mounts and rear cross-member. 600lbs of twist should be fun:)

I agree. I think you will have tire spin, u joint break, axle break or clutch slip before you twist a frame. mark