What torqueflight 727 transmission rebuild kit do I need????

Hey all,
New to this site because I'm approaching new ground. Never done much to a transmission but I think it's time. I'm dropping a 440 in my car soon and I need my torqueflight 727 to hold up. I've read around and I've heard I'll need a 16 roller sprag along with a valve body and rebuild kit. Any recommendations on good kits?

I saw OPT has a pretty complete kit but I can't find much on it. Any thoughts on this kit?

I looking to daily this car during the spring. Would there be any problem as far as durability of the transmission if I were to use a reverse manual valve body?
I new to this(just got my license:lol:) so feel free to tell me I'm wrong.
Thanks for any input!!