Will I have issues with frame twisting with this setup?

1978 Datsun 280z, LS2/T56 swap from an '05 Pontiac GTO, stroked to 427 ci, forged bottom end, heads/cam/intake, approx. 550rwhp, Ford 9" rear end, 4.10 gears, 10 inch width wheels running 275mm tires, 8 point roll cage. Looking to be able to launch a decent wheelie on drag slicks and not twist the rust free frame.

Yes you will.

Definitely. The frame is expecting torque from a small six cylinder.

If you were stupid enough to make that swap---- knock yourself out.