The sprag in the 400 is the weak link
and no OD, and it will need some billet stuff as well.
A friend and I just recently found out that the 400 has a specific way it needs to be operated to be gentle on the sprag. He bought it/did the swap thinking it would just handle what he could throw at it and he just lost his sprag (34 element) with less than 1.5 k on the car.Now this was due to his builder failing to mention teh sprag thing and honestly we didnt see anyone else mention it on the boards.
Things we found out that we were not aware of with the 400 that is now needed with it. Mind you my buds power level is low 10's/high 9's and has a reverse manual VB and transbrake.
A few new methods
2nd -3rd gear burnouts
Not being able to ratchet down to second and just stomp it when you want as in street racing and someone rolls up along side.
And there are other factors as well.
Call a good builder and ask him about the sprag and the do and donts/new driving style with the 400.
The 200 can hold at the power level you are asking about. And it needs to have good parts as well. The 200 will need freshening frictions wise vs. the 400 IMO
I would go with Lonnie Diers at Extreme automatics 513 898 0533 for either and call him for his advice as well. Just leave a message they'll call you back if they dont answer. They just merged with another business and the phone messsage may not say extreme automatics.