Using 8 3/4 with /6

Very nice car!

and OH MY GAWD. Let the kid run whatever rear end he wants to. Will an 8 3/4 take more power to turn? Yeah. Are you runnin for money and points in a drag race? Probably not. That 8 3/4 will last virtually forever behind a slant. Unless you want something to eventually BREAK, I don't recommend welding spider gears. It's a stupid thing to do for everything except going in a straight line, IMO.

As I said.....NICE car. Good luck!