I have an 88 lx vert. Even with only CAI, 4.10 rear, and exhaust, it is hard to reliably put power down. I can't imagine what that much torque would do to one of these chasis. Yes with Full length subs, 3point strut brack, 2 point shock brace, 4 point kmember brace and a full or partial roll cage, panhard bar (maybe torque arm) and some new stuff in the front He would be golden, but
A) he never said he was going to
B) That takes a decent chunk of cash to do right.
*Edit* I am assuming that you are not keeping the 429 stock, as its a 50+ year old engine that is inefficient and not super powerful in stock trim *Edit*