Motohead,
I bought a Lentech VB, non locking converter, cast pan and hardened inner shaft and then had Mark Twain Transmissions on St. Charles Rock Road rebuild mine with using that stuff and their performance package. It included extra clutches, kevlar OD band and some other stuff I can't remember. They said it was good for more than 600 HP.
If doing it again, I'd just buy the complete transmission from Lentech. And yes...you need more cooling. I'm using a pair of 24K GVW B&M coolers bolted back to back with an 800 cfm fan.
Where in St. Louis do you live ? I'm in St. Charles.
David