71 K10 3 speed upgrade issues

[chevytruckguy70]

I bought a 71 K10 rolling chassis, no engine but 3 speed trans attached to the transfer case.

I have a 72 2wd 350/350 c10 I'm taking the body and engine from to complete the truck.

I also have a sm465 4 speed from another 2wd truck.

My original thought was to use the 4 speed, but of course it needs the tail shaft to be converted to fit.

Is it easy to convert the SM465 or the 350 auto to bolt on to the transfer case?

I found a 700R4 out of a 4x4 that's had a GM rebuild done to it but from what see I would an expensive adapter to connect it.

The 3 speed needs to come out, what are my options?

Thanks guys

[74CustomK20]

That sm465 will need a different spline transfer case unless you run a divorced. That th350 will have a 27 spline output and should match the spline of that 700r4... Also if you are wanting to gain overdrive the sm465 will do you no Good... What's the plans with the final product?

[chevytruckguy70]

My original plan was to just put my th350 in and make the truck an automatic because I'd like a daily driver, or at least several days a week. I have collected quite a few parts for 4x4 (high hump, shifters, wheels etc) and since the truck is already a manual I considered using the 4 speed (2wd) just because I like driving a stick although that may get old every day.

I ran across a 700R4 out of another 4x4 and thought that an overdrive might be nice.

So, as you can see I have a toy or what I call a man's lego set and I need to locate all the parts to put something together. Ideally, using the parts I already have would be great, but I am finding out that may not be possible.

I just ran across a "rebuilt" 400 turbo with its matching np205 from a 70 chevy so maybe that is the way to go.

I see you're not far from me, do you have any parts laying around that you might sell?

[Mike C]

The 3 speed is attached to a Dana 20 if memory serves and not a 205. I would find an SM465/205 from any truck from 70-until the late 80's. Anything with a bolt on (no slip yoke) u-joint setup.

I much prefer the 4 speed to an auto in my trucks, but to each his own.

[special-K]

When my only experience with 3spd 4wds was a Blazer, I thought the Dana 20 case came behind all 3spds. But, I got a '71 K/10 SWB and that had a NP205. After looking around, I think it's only K/5s that used the Dana20? Anyway, we need to know what you have, first. I am not sure, but I think I checked around and the NP205 adapters are different between the 4spd and 3spd...maybe the shaft length?

I think the easiest and cheapest solution here would be get a NP208 with adapter to use behind either your TH350 or that 700r4. You could also find a complete trans/transfer case combo for a reasonable price. To use a 700r4/NP208 combo there is no adapter required and you just mover the engine forward to the 6 cyl location to make up for the longer 700r4, no driveshaft work required

[Bigdav160]

I am not sure I would call the 700R4 to NP205 adapter expensive.

But I understand we all have our bias.

[chevytruckguy70]

I've cleaned a few areas of the TC and have determined it is a 205. The original goal was to try and use the parts I have on hand but I've located a TH400 with a 205 attached and also a sm465 with a 205 attached. Now I need to figure out which one to do. The 465 is probably the way I will go.

[74CustomK20]

Chevytruckguy pm sent.

[chevytruckguy70]

I've cleaned a few areas of the TC and have determined it is a 205. The original goal was to try and use the parts I have on hand but I've located a TH400 with a 205 attached and also a sm465 with a 205 attached. Now I need to figure out which one to do. The 465 is probably the way I will go.

[special-K]

Originally Posted by Bigdav160

I am not sure I would call the 700R4 to NP205 adapter expensive.

But I understand we all have our bias.

It's more a matter of labor cost in this case