Big Inch Torque Monsters: Who has them?

[Purs]

I'm building a pump gas 496 (I know, it's not that big anymore....) and am going back an forth on whether to drop it into an early A-body GM car (Chevelle, Buick GS, etc) or a '68 SWB that I've got my eye on. Without going into specifics, this engine will be making a conservative 650HP/600TQ. This is NOT a strip only vehicle. It will be 80 percent street driven with an occasional trip to our local 1/8th mile strip. My question is, you guys that have experience with trucks and this level of power, what upgrades are neccessary for safety and reliability. Here are some specific areas I'm concerned with:

1. engine towers/motor mounts
2. driveshaft
3. Rear end (I have a chevelle 12 bolt I'd like to use with Moser axles, etc...)
4. Frame flex/twist under heavy accerlation causing cab/body distortion

Anyone that has experience please share.

Thanks In Advance!