When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
A TH200R4 is a more direct swap in for a TH350. No changes have to be made with the exception of a shift kit to reflect the added position, and moving the cross member back a little bit. The drive shaft goes in, and so long as you have a multi fit case it'll bolt right up to your motor.
There's lots of information here on this forum, many swapped in a 700R4 or a 200R4. It shouldn't need any tunnel clearancing or cutting - the 200R4 is an easier swap
200 4r is an easier and cheeper swap, and lighter weight too, and doesn't have some of the inherant design faults of the 700, like the 3/4 clutch pack...which suffers greatly from overheating and premature burn up....light duty it's fine....like it lasted 5? years in my '72 336 geared 350 engine vette here...but when it started to go I did my own 3/4 clutch pack...and 3 years later it was time again....nevermore....
I redid my own 200 4r and i'ts a much simpler tranny, and so far after 8 months or so, it's fine....
The 700R4 and 200-4R are both 4 speed OD trans. If biult right, both will handle a lot of power. The 200-4R is easier to instll because it is the same length as the TH400 and TH350 so you don't have to shorten the driveshaft. 200-4R install
both transmissions are great... The TH200R4 requires much less modifications to install and uses less HP and is lighter than the TH700R4 but you can't go wrong with either transmission...
What engine will you be putting it behind? If a big block I'd use the 200R4. I had the 700 behind my big block and found first gear to be too low even with a 3.07 rear gear.