1986: np208. 700r4---->th350 swap, need advice

[Walts_restoration]

For my 86 k5, i wanna swap the 700r4 in favor of a th350. I dont really care about the overdrive or lower gear ratio, i plan to tow and play with this truck, so i want it to take some moderate abuse.

I know the 82-84 or some years in there used a th350 np208. What all is different between these tcase/adapters and the 700r4s? i thought i read somewhere the th350 and 700r4 can swap without any modificaions.

edit: just found out they are different.

Originally Posted by 1-tonmudder

In about 1981 GM starting usin the 208's behind the Th350's.It was only a 1-2 year deal until the 700R4's came out.The 700 and 350's both different adapters.

The Th350/208 adapter,trans side.


By 1983 they were using the 700's and it required another adapter.

Trans side.

So how easily do you guys think ill be able to find a trans and adapter? im gonna call a local 4x4 place see if they have the right trans and adapter, if not, what different transmissions will work (correct length) anhd do you know a place where i can get the right adapter bracket? Will i need to swap the cross member too? im new to this 4x4 stuff and trying to learn before i walk the wrong path. Oh, and i dont wanna worry about a lockup converter, its unneeded in my books.

(the main reason i want to use the th350 opposed to the 700r4 is the engine i have came from a 75 blazer with a th350 np203, so everything motor wise is setup for a th350 already, and plus they are more simple in my oppinion)