Awesome project, light car, good handling, and with a few mods it should be a rocket that handles.
And it is a pre-1976 vehicle, so no smog inspection requirements here in the Golden State. Nice starting point.
How much of a weight change do you expect by removing the iron in line 6 and replacing with the LS engine? As I recall the SBC swaps in the past made the car a bit more heavy, but the weight was more central to the car so to wasn't a big sacrifice, as it helped transfer some weight toward the rear. Do you have a target weight after the car is done?
Also there's a lot of room up front in the engine bay. Any chance your gonna use a turbo or pro-charger with all that real estate in front of the engine?
Have you seen the yellow Z-car at the Good Guys events in Pleasanton? I think he's running a SBC, with a cage and other mods.