Gunslinger,
Welcome to the forumns. I just sold what was my first boat. It was a 76 Hondo sprint bottom.
As far as the turbo 400 I have never run one in a flat. Alot of guy's in the forumn's have, you should get some advise.
I would highly recomend hooking up with a local v-driver in your area. I wasted alot of time & money on my boat until I got some help.
Personaly, I would not run the turbo 400. The added weight & reliability pretty much kept me away from the tranny. If you are going to use the boat as a cruizer, the tranny could be a cool deal. If you are building it to be a river racer I would not recommend the tranny.
Good luck with project. Let me know if you can't find any v-driver's in your area. I know a couple of circle race guy's in so. cal.
Morg.