LT1 350 would have been nice, but by the time Sandman came around SBC's were lame ducks and one of the reasons why the 400 wasn't put into HJ was it was basically line ball with the HJ spec 308 performance wise and significantly lighter. We all know how badly the HX 308 suffered under ADR27A compared to the HJ 308, at least we still had decent fuel. The USA went to ULP circa '72 so imagine the HX 308 dropping back to 8.5:1 and you get a feeling how bad the run of the mill passenger 400 might have been. Probably the best we could have hoped for in 1974 would have been a 455 Pontiac engine.