What is the best way to get an overdrive auto in a 67 Barracuda?

I put one in my 1967 notch. Stock exhaust manifolds with accurate dual exhaust. I lowered my transmission crossmember 1" to get tunnel clearance. Tight fit but it is in and I am happy with it. Stock out of box they claim something like 750 hp and can be ordered up to 1200 hp. Like anything it is a lot of work and studying to do but worth it.