Tranny Recommendations for 600 HP

I love the idea of overdrive transmissions. I am not sure though, that it would be cost effective at your intended HP level to build one. The GM 200R4 is a great transmission, but it's gonna take some dough to make one live.....but you can certainly do it. Course the A518 would be a great choice, if you didn't have to rebuild the whole frikkin floorpan. That leaves the GM 700. Not the most optimal gear ratios, BUT it is more popular and that could save some coin in building for that power level. If it was me, I would just build a warmed over 727 and be done wif all dat. They'll hold up at that level with no sweat.