what trans to use for road race?

You'll still be driving a brick with that big block. Seriously build either a late 80's-early 90's 360 (or 318) roller block or a mag block 360 (or 318) and don't look back. If you look up autoxcuda, he has posted up video of his 408 runnin strong!

416 :burnout:

340 block .030 over with 4.00 scat crank... About 130 mph/6000 rpm before hitting the binders down for turn 1

[ame="http://www.youtube.com/watch?v=vTT--mGlpTY"]Spring Fling Speed Festival 2011: '68 Barracuda "S" - YouTube[/ame]