66 c20 to 4x4 conversion

[MYBAD66]

Hey yall, So I have a 66 C20 with a 305. But I'd really like to have a 4x4 personally, and looking at 4x4 trucks in my year they're all pretty uh out of my price range. So I was wondering what parts I would need to convert my 2wd into a 4x4 truck and where I might need to get them. Are parts interchangeable between years where I could find a donor 4x4 of a later year that I could use? Or do I need to find my exact year range? Or is this gonna be harder than I thought and would have better luck converting over to a later year everything? Tips and tricks are always helpful. Thanks forum!

[duallyjams]

This is one question that gets asked a lot, best answer is do a search and take your time and read a lot of threads.

[franken]

Ask yourself if you want a K10 or K20 (or 30).
I'd be thinking of a square body (73-87ish) but not one with an NP203. Decide if you want an NP205 or NP208 (or 241 if I recall) and start trolling CL...

Why? There are billions out there, so the cost is less. The '60s closed knuckle (?) front diffs are sort of antiquated.

You need a different trans, or at least another tailhousing and probably tailshaft, so start a list:

Trans
TC
TC shifter, boot, etc.
Crossmember
driveshafts
diffs
springs, hangers, and frame mounts.
wheels and tires.

I'd be looking for a whole truck to get the parts from to get every part. Piecing it together would be a pain.

For example, there are 2 square blazers on CL in my area not running for sale now, or were the last time I looked. The running gear would be the same as a K10, but the springs might be lighter duty.

The trouble w/ squares is the spring pads on the rear diff are further apart, and the springs are longer. So you need the riveted on frame mounts for the springs, or another diff. The C20 diff in your truck may work if the ratio is the same, or you can find a new R&P. I think parts for those old diffs are about gone. As I recall, the early square 1-ton cab and chassis rear diffs used the same spring pad width as 67-72. I'm guessing 66 is the same as 67-72.

I was planning to use a 91 K20 Sub as a doner to make my 72 K10 into a K20 but decided the D44 and SF10 bolt weren't worth the effort. I also wasn't sure the we buy junk cars people were going to come get the husk of a nonrolling Suburban from my driveway, or if my neighbors would be thrilled. I decided that torching the truck to bits that were light enough to lift, while fun, could also enrage the townsfolk as well as draw the popo. I took the NP205, driveshafts, BH, clutch, etc. off the Sub and parted the rest for $700 more than I paid for the truck...

If you like a manual trans, you may want to think of an NV4500 to get rid of the farm 4-speed that's probably in there now.

Just some thoughts...

[andrewmp6]

Look around the 4x4 build threads you will find a few that have done the 4x4 swap.

[LONGHAIR]

As always, the point of conversion is exactly that.....converting something that is not available that way. If you want a square body Chevy truck.....buy one.