727 for a 700hp big block

I just bought an indy 500 inch motor to put in my duster, and need a big block tranny. I saw where TCI makes one that is supposed to handle like 725-1000 plus hp and was wondering of any thoughts or better options were out there.

I ran a TCI behind the small block with great results so I was thinking it is a good choice unless I can build one for cheaper than about 1300.