I prefer the subframes from Fatman Fabrications. They have some that use GM "G"? Body components (Nova parts) that I think will work better on a heavy ride.

Using a stock Nova (Apollo, Lemans, Omega) subframe is too wide for a pre-50's ride. Fatmans subframe is narrow but it uses the heavier duty parts.

Have you ever driven a Mustang II with a V8??? Not a good ride at all