The problem I had when looking at the frame connectors, is the attaching points...I didn't see how they were going to add any stiffness. They seem to connect the wrong things together. Being an engineer messes up one's perspective, I guess.
Oh, and go ahead and replace that stock rear end. I destroyed mine, split both axle tubes wide open wrecking the drive shaft in my 62 with a worn out tired small block. I installed a 67 Chevy II 12 bolt posi, problem solved! Good luck with your project!
LOL you really only need them if you hook up. Actually a true "Sleeper" probably would not have a roll bar or cage. They only street race, once you roll into the water box you have lost sleeper status.
...if you really want to mess with peoples heads why not an OHC Pontiac six? Not enough? Put some pressure on it with a turbo. Would be fun to tell the guy you cleaned his clock with a banger. Now that's a sleeper in my book. -Dave