Frame connectors on a street car

My 70 340, 4-speed swinger is (hopefully) heading to paint next month and my painter buddy is insisting on installing frame connectors. The cars has front and rear torque boxes and should be around a high 12 sec car. He wants to make some that protrude through the rear floor pans. Seems like I could get away with the us car tool weld on ones? I am also seeing us car tool has a a-body bolt on frame connector now. Has anyone tried these? My painter friend has been telling me horror stories about freshly painted 4-speed cars cracking the paint due to twisting. Do you guys think the weld on, under the cars ones would be okay? Thanks all! :burnout: