200R4 converter help!

[NutlessCutlass]

Howdy!

Brand new to the forum here...a friend sent me here and said you fellas were pretty knowledgeable.
Here's my issue...and you'll probably smack me. I'm building a SBC for my '85 Cutlass Supreme. (I know, a Chevy-powered Olds doesn't belong here...at least it's a G-body!) but you guys have experience with the transmission selection I have, and I need help selecting a proper converter, since I know next to nothing about them. The 350 is in the 400hp/450 ft-lbs torque arena, with a torque peak around 3600rpm. I'm running a (I believe) 7.5" 10-bolt limited slip with 3.08 gears (for now.) out of a '78 Grand Prix. As soon as I ascertain for real which carrier I have, I'll be running Richmond 4.11's out back. I scored a universal bolt-pattern 200R4 out of a Monte SS. My question is this: What will I need to do to the transmission (it's box-stock, 70k miles) to hold up to bracket racing and general honda-smacking street use, and which torque converter will suit me best? I'd like to go for a high stall speed to match my torque peak, but I'm having trouble finding 200R4 converters. Anyone experienced in these matters that can stand offering advice to a Chevy/Olds combo goober?

cheers,
-Drew