TH400... For now.

[astroracer]

I have decided to go with a TH400 for the Bad Ast project. I can't find an OD auto that will live behind the 509 that I can afford. The 4L80E is about the only viable option and I just can't afford the electronics so, I am going with a "dinosaur" trans that I can build affordably. The light at the end of the tunnel is a Gear Vendors Unit. I will save my pennies and do that in a couple of years.
Any advice on the 400? What should I have done to make it live behind a 550 horse BBC? Any local vendor recommendations. Flint or Livonia areas.
Thanks
Mark