Being killed by an airbag's more appealing? To my knowledge all A bodies have collapsible columns after '67. The self-tensioning shoulder belts became pretty much standard fare in cars in '74. To me the little cars being called muscle cars never really seems right- there's a world of difference between a Satellite and a Duster and it's more that they're different than that either's worse. Of course they are about as light as a stout body will get so that can be pretty dangerous in an idiot's hands.
Rusty Rat made a pretty good suggestion. If you're planning to go hydraulic roller, unfortunately it just makes good sense to get a Magnum 360 to do it. Not a whole lot more to add other than that piece of if you want a roller cam SBM, buy one and then build it from there.