80's 700r4/np208 swap into 70's th350/np203 truck

[4x4blaze]

Hey guys, I recently acquired a 75 full top K5 with a th350/np203 combo that I am starting to build. I also have an 87 K5 (that is being saved for a project later down the road) but will not be running for quite some time. Well, I would like to steal the 700r4/np208 driveline out of it, and put it in my 75.

I know this swap has been done before and was wondering if any of you guys have experience? I can see that the crossmember underneath the transfer case is different and I believe the 700 is longer than the 350. Am also swapping axles from the 87, along with the driveshafts

Thanks guys!

 

[Justin V]

If you have both trucks, should be a breeze. Only thing that might bring the suck is throttle valve cable attachment to the 75 carb and t-case shifter. Both won't be that difficult.

 

[Justin V]

What's wrong with the 87? If you swap the TBI into the 75 you'd solve a few problems at once and also have a boat load of work to keep you busy.

 

[4x4blaze]

What's wrong with the 87? If you swap the TBI into the 75 you'd solve a few problems at once and also have a boat load of work to keep you busy.

Well, the 87 was literally a mint condition truck that I've had since highschool. But unfortunately I was in a pretty bad accident that tweaked the firewall and bent the frame. I am holding onto the body and do plan to resurrect it someday, but I do not have the time or space to tackle that huge of a project right now.. so, I ended up stumbling upon a 75 full top K5 that is in pretty good condition that I am going to swap all of my ORD parts that are still good onto, and continue where I left off with my build. It's still very upsetting to me, but its life. And unfortunately sh!t happens.

But anyways, the tranny and transfer case seem to be fine. I pulled them out of the 87 today. And I'm actually not worried about the tbi setup, because I have a full roller, full forged 383 with a sniper EFI setup that was ready to go in the 87, but will now go in my 75. So I realistically just want the driveline. The 700 will be built or sent in as a core.

 

[4x4blaze]

One question I do have after looking at my 87 today is about the np208 shifter? Will the shifter mechanism fit inside the 75's np203 shifter hole? Or am I going to have to patch the existing hole in the tunnel and relocate it?

Thanks!

 

[Wes Harden]

I had to cut rear part of the t case shifter hole to clear. I made a patch pannel to cover afterwards. 700r4 and np205

 

[AZK5]

I did this exact mod a year ago, 1988 700R4, NP208, and driveshafts into my 1975. I retained the 1975 shifter handle in the original hole but made a new bracket that allows it to align with the NP208 shift link rod. I'll try to get a picture, I'm bad about taking pictures of my creations. I kept the Dana44 and 12 bolt and used a conversion u-joint on the rear driveshaft 3R to 1330. I put a 1330 yoke on the 12 bolt. The cross member front bolt hole lines up with the rear hole on the frame so I only needed to drill the rear two holes.

 

[4x4blaze]

I did this exact mod a year ago, 1988 700R4, NP208, and driveshafts into my 1975. I retained the 1975 shifter handle in the original hole but made a new bracket that allows it to align with the NP208 shift link rod. I'll try to get a picture, I'm bad about taking pictures of my creations. I kept the Dana44 and 12 bolt and used a conversion u-joint on the rear driveshaft 3R to 1330. I put a 1330 yoke on the 12 bolt. The cross member front bolt hole lines up with the rear hole on the frame so I only needed to drill the rear two holes.

Good info to know, thank you!

& I think I may have also found another solution to the shifter. I searched on the internet for a little while and actually found a really nice cable shifter, so I think I may give it a shot!

https://jb-custom-fabrication.mysho...y-of-cable-shifter-single-np-231-p-n-np231-cs

 

[tenderfoot]

You should do a build thread on this. I would imagine there are others. But it seems like this would be a fairly common swap that many would be interested in reading.

Shoot, when this thread is ready you could probably ask a mod to move it over to builds.