The rear end is a good place, that was the first thing to go at the strip on radials when I increased power over 500whp. 31 spline axles and yukon carrier with a tko trans have lasted fine. At the time I had a 331 with a blower and the main caps were chattering at that level. Next item was the engine (i went the 351 route),then cooling, then the fuel system.
94 yellow gt 704whp 753ftlbs @16lbs: E85, F4TE 351w, probe pistons, Z304DA heads, anderson b451 cam, trickflow R intake, Precision 78mm turbo, ID 1050's, tko500, Mcleod extreme clutch, 3.31's, quarterhorse/binary editor.