there is a chance my tranny is going out on me, i was wondering if i can put a th350 in there, i have a 700r4 right now, wich one is better???

also if it's possible will it take a grip of work to get it in there "modifying stuff etc.

 

"Better" is too subjective. Better at or for what?

The TH350 is more common, cheaper, simplier, etc. Perhaps even a little stronger, depending upon how built.

Those things don't necessarily make it "better", though.

If you want to know how it will feel, put the TH700 in "D" for a day and see what you think. Like that buzzing going down the highway? That's not the total picture, though, as the TH700 also has a higher number ratio first gear, meaning your coming-off-the-line performance will be diminished with the TH350.

Putting the TH350 in isn't the hardest thing out there to do, but it's no walk in the park, either. You'll need a different cross-member, torque arm and driveshaft unless you get a 9" tailshaft TH350.