K frame lowering blocks

I would go for it, You are talking about 3/4" drop in 35" of torsion bar. It wont make a big difference.

That isn't really germane. The torsion bar is designed to carry a load in rotation (transmitted through the control arm). This would add a straight vertical deflection load. It is not in any way designed for that.

I don't understand why the SS cars would have had spacers. They had enormous hood scoops — there wouldn't have been any kind of hood clearance problem.