Not to be rude but that rear shackle mount is pretty cheesy. They should have drilled thru the frame and welded the tube in with washers welded to either side. I'd be mad if I paid for that.
I personally would backhalf that car. But, telling someone that any big block making decent grunt in an A-body needs to be backhalfed to hook, is someone who doesn't know how to correctly tune suspension. Bad advice, period.
Cool, hope you had fun!