1973 C20 4x4 conversion
 

Hey guys, i'm new to this forum and im sure there is similar threads to this one out there, but i need some good info pretty fast so thought i would try a new thread.

So about 8 months ago i purchased a 73 C20 2wd auto with a 454. IT was cheap and had a straight body. The other day i came across a 1978 C20 4x4 up for sale as a parts truck for $200 so i bought that as-well (don't worry this is leading somewhere).

I was wondering if due to the same size,body etc how easy a 4x4 conversion would be. I understand it can be done however, the new donor truck has a 4 speed in it that looks pretty beat up, so i was wondering if the transfer case would bolt onto my existing transmission. I believe the transfer case is np205 or something like that.

Also any other hints, heads up, or how to's would be great for this project.

Thanks.

Re: 1973 C20 4x4 conversion
 

Are you thinking of a body swap or a suspension swap? Neither one is a bolt-in because of the frame differences, but IMO the body swap is somewhat less work.

Assuming your 454 has a TH400, you can get an adaptor for the 205.

Ray

Re: 1973 C20 4x4 conversion
 

Yes it is a t400. I was thinking about doing a body swap, however upon comparing frames, the one from my 2wd is in a lot better condition, so yeah, i think its going to be a suspension swap.

It's definatly going to be a interesting project, luckily my cousin in law owns a shop and said he would help me out.

Does anyone have experience doing such a swap ?

Thanks.

Re: 1973 C20 4x4 conversion
 

Personally, if your 4x4 frame is too rusted, I would find another frame. They are a dime a dozen from 73-87', and relatively cheap. Also, your th400 will not bolt up to the transfer case. You would need a th400 out of a 4x4 (I think, K case) and adapter to bolt up to the transfer case. Personally, I would sell some the parts off of your existing 4x4 chassis, and buy another chassis. The frame must be pretty nasty as you are california, and they are typically a lot cleaner than found around here. To me though, it would be much more work and agrivation to make a 2wd chassis work when there is an abundance of 4x4 chassis' around. Trevor

Re: 1973 C20 4x4 conversion
 

Sorry, I didn't mean to imply that you could bolt your TH400 to your NP205 using factory parts. You would need to get an aftermarket adaptor like this one.
http://advanceadapters.com/product/1691/50-3201.html

Before you shell out $600 for this kit, you might want to check the used parts market. It is entirely possible that you could find a factory 400/205 assembly for less money.

Ray

Re: 1973 C20 4x4 conversion
 

Depending what 400 he has he can bolt up a 205 to it. Check this link out..


http://coloradok5.com/forums/attachm...3&d=1174708677

Re: 1973 C20 4x4 conversion
 

Thanks for all the information. Hopefully this project will be going ahead in the next few weeks, so i will update on how it goes and maybe troubleshoot with you guys.

Is there the possibility that the sm465 would mount up to my 454 (if in decent working order of course) ?

Re: 1973 C20 4x4 conversion
 

If your TH400 has a big "HD" on the bell housing area, it can bolt up to a NP205 with a factory adapter.

You'll find the adapter in 70s GM 4x4 trucks- it'll be bolted to a NP203 with a cast iron housing (the old ones). That same adapter will work with the TH400 / NP205 setup.

I know this because its exactly what I did.

Re: 1973 C20 4x4 conversion
 

The sm465 should bolt up to the 454. That's the combo in our 87'. Trevor