We have a late 70's TT500 that my uncles were rebuilding but they couldn't finish it because the head studs wouldn't screw all the way in. Then it say for a LONG time and I just recently got it free again (I tried standing on the kicker and everything but a little carb cleaner and spray lube and it broke free WITH MY HAND). It also needs a header(s) so what would be a period correct aftermarket header for it? I'm assuming Cobra but what's something else that might've a little harder to find but make it that much more unique?