Im gonna be droppin in a th350 where my old 700r4 use to reside, just for the sake of durablity and being a little cheaper. I wanted to know if thier are any problems in doin this. I know i have to have the 9 inch tailshaft and the hurst conversion kit, but besides that, is thier anything else. Also, my car came with 3.73's from the factory, and was wondering how many rpms my car would be turnin at 55. It has p215/60/r15s. So in 1:1 what ya reckin she'll be spinnin at. thanks a lot yall

 

about 16 mpg, er, I mean 2200 rpm...

 

so you think i should go up a tire so, or would this be acceptable and not kill my engine. What about the rest of the install, am i gonna run into any problems? I think its pretty much straight forward. I been toying around with buying just a used th350 b/c i have heard that there a lot more durable and stay in better shape even with a few miles on em.But i also need a torque converter, meh.

 

Why change to TH350? Is the 700R4 dead? You will just be changing from a 4 speed to a 3 speed. The TH350 is not any more durable than a 87 and up 700R4 or an early one that has been updated. You don't have to take my word for it. Read about swapping here:
http://www.transmissioncenter.net/700R4.htm
To see what RPM your car will turn, just run the 700R4 around in "3" for a few days. It's exactly the same 1-to-1 that you will have in top gear with the TH350. While you are doing that, think about gas mileage. If your car had 2.73 gears it would probably be liveable, but with 3.73's it's gonna get lousy mileage.

 

Also, by the time you add the cost of the conversion kit and shortening the driveshaft, the used TH350 will cost you more than a rebuilt 700R4 so you won't save any money, not to mention what you will pay in gasoline from now on.