Transmission and transfer case swap

Oakfan707 · Dec 15, 2019

I just bought a 86 k10 with the 262 v6/ sm465/np208 set up. The motor is clapped out beyond my wanting to repair. I'm just going to throw a different v6 in it for now until i can get my house built and everything to do a small block conversion. My question is this.... i would like to swap the motor for a different v6 and change to an automatic transmission. Is there anyway to do this without changing anything else. Like a direct fit drop in and be done?

bucket · Dec 15, 2019

I guess it depends on what qualities as direct fit. Do you want to keep the same transfer case? It's a 32 spline input that you gave currently. The closest thing that could bolt in with almost no modifications would be a TH400 with the long 4x4 style output shaft, along with the 6-bolt (round pattern) transfer case adapter. Linkage and shafts would stay in the same place.

But honestly, I wouldn't do it. Compared to the SM465 that's already there, an auto trans will make the V6 feel rather doggy.

Oakfan707 · Dec 15, 2019

My engine already really doggy. Think i could just buy a different v6 like say a 1990 and just swap that out instead? I have no idea what spline counts will let me interchange with what i have

bucket · Dec 15, 2019

All the 4.3's bolt in the same, but the injection setup changed a few times over the years. If just swapping the long block, there's negligible power increase with the newer engines.

Oakfan707 · Dec 15, 2019

Thats awesome thank you a ton. I didn't want to buy a different engine and my transmission not work. Any 4.3 will give me more power then i have now for sure. I'm trying to learn and research as much as possible on these trucks. Thanks again i appreciate it greatly

80BrownK10 · Dec 16, 2019

Yea the tail end of square bodies had 4.3 factory.

I would out in a 4.3 if that's what you want but keep the 465 trans. Those things are bullet proof and you won't have the losses from the auto.

4.3s share same bolt pattern and bell housing as the small block so they will bold up to the same trans.

Transmission and transfer case swap

Oakfan707

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