Tme for a new tranny... 700r4 questions

[steves1967]

I changed the fluid in my TH350 today, it had enough copper in the pan to make a new penny! I noticed the tranny slipping awhile ago...anyway I'm going to go with a 700r4 but what type?? Lock-up, non lock up, computer controlled.... I 've got a carbuerated 71- 3/4 ton long bed. I need some suggestions and some help- I tow my 67 firebird drag car to the track alot so the tranny has to be strong... Thanks for the help