I bought an '87 K5 Blazer. It has a 350 V-8 4 bolter with TBI. The truck is solid and runs great. I have replaced a few sensors and things but my latest investigation has turned up some questions. The previous owner took out the 700R4 and put in a turbo 350. I have no idea why. I contacted Monster transmission to price a new 700R4 and the question was raised about the transfer case. Yikes... So I crawled under the truck and it is a NP208 C 2. Aluminum case. They told me these were usually behind the 700R4. So I guess it is safe to say that who ever did the swap left the transfer case alone? It also has 251 gears in it... What about this adapter stuff I read about? how do I know what I have. Driive shaft lengths and all so I know what I need besides the 1600 dollar conversion kit? I do not want to strand the truck. I need all the parts on hand before I tear things down... Any help or experience would be great, thanks

 

the th350 and 700r4 use the same output spline count (27), which means is if you find a 700r4 to put in the truck that transfercase will bolt right up as long as you have the adapter for the 700r4. i dont have any experience with the factory th350/np208 combo so not sure if that adapter is the same or not.

i see it all the time where people throw in th350s, 700r4's are usually more expensive to build so people just throw a th350 into the truck, even ive done it on older k5 blazers.my guess would be the driveshafts are going to a different length then you need because the 700r4 is a longer transmission then the th350.

would be great if you can just find a donor truck with everything attached