Well bad news for me is my original TH350 tranny for my 69 bird was stolen from the dealership that did the rebuild. Just got it done and with a B&M Shift kit in it all ready to go and it turned up missing. They feel they know who stole it but video didn't catch it so I doubt I will ever see it again. Frustrated is beyond words but they are reimbursing me nicely. My question for now is I have a TH400 I took out of a 73 Grand Prix years ago. It looks like it will bolt right up to my 350 Engine block but are there other factors I need to consider if I have them use that one. Such as tranny length, kick down, cross member and etc. I have read vague things to all of this but I am not a tranny person and it raises lots of concerns for me if it will work. It looks like the slip yoke is heavier duty but will still connect to my same driveshaft too. Its been many many years since I took this out of the car but could a '73 TH400 have overdrive? I seem to remember it did. Thank for any advice on this. Always appreciated.