[LS short box]

Don't know if this helps but I always run the biggest radiator I can fit. On my 68 with I ran an Afco LS generic swap radiator. They make the same size radiator for a SBC. Got it from Speedway Motors. Had to mod the upper and lower saddle mounts a bit because the radiator is thicker than stock.
I'm guessing it wouldn't take much fab work to get your stock fan shroud to work. I reused the stock upper mounts but shaved the shroud mounts.
Struggled to get 160 on cool days.