C20 dually conversion

[72kool]

Ok before i start, im sorry if this is a repeat of other threads i have read through a lot of threads and post but did not find exactly what i needed.

i have a 1972 gmc C20 with a dana 60 rear end and 4.10 gears. it has the trailing arm and coil spring suspension.

i want to convert it to dual rear wheels. i understand i could swap axles and get this but i want to keep my dana 60 and try to just bolt on dual rear wheels. why do this?? first is, its my way to be different from other trucks and it is useful to me. also i want to keep my dana 60 because i have it now, and i can keep the 4.10 gears vs having 4.57 or 5.10 (not positive on exact numbers of the lower gears)

can i just bolt dual wheels on? do i need longer studs or a spacer? where can i purchase any of these parts ?

as for making them fit i have my own ideas as to wheel well fitment. i want a more tucked look and not have a large fender on the sides. i will try to post a picture of what im trying to do.

also i have heard that i may need a larger wheel than 16" because of the drum size. can anybody confirm this?

i know that just putting dual wheels on does not increase its capacities, it will get me the look i want though and i plan on boxing the frame and installing air bags instead of coils on custom trailing arms. this sould beef up the suspension some. i could get a c30 and it would be easier, but i like to be different and do it my own style. any help would be greatly appreciated

the first picture is the what i am trying to do. if this is a members truck, please tell me more. i want to keep the front wheel the way it is. i like that look better for now.

[LONGHORN1962]

I have done two of these. The 16's will work fine you will need longer studs. If you are using the factory bed you will have to trim the inner fenders. If you have a good auto parts store close they can look up the dimensions on the wheel studs. Back when I did mine the studs were an off the shelf item, I believe we used 73 C30 studs.

[72kool]

ok thanks. i will look into them. what wheel did you use then ? what years fit? i found these online and look like they would work but would love to have a for sure part that somebody has used

https://www.southwestwheel.com/p-1836-29588pkgry21.aspx

[72kool]

also do you remember how much did you have to extend the inner wheel well? i want it to be as minimal as possible for maximum width between them

[LONGHORN1962]

If memory serves it was 4 inches. We actually did a total conversion, front wheels and all. We used a 73 P30 bread truck on one and a 79 C30 on the other. You can probably find good used wheels at the salvage. Be sure you buy Chevy wheels so the center hole is the proper size and get the retainer rings that go between the nuts and wheels.

[72kool]

Where these on leaf spring or coil spring suspension trucks? Also how much space did you end up with between the tire and frame?

[LONGHORN1962]

Actually one of each. I am thinking it was 3 to 4 inches.

[72kool]

good information to have. so to recap, you used dually studs from a 1973 c/k30 and swapped them into a dana 60 rear and used the wheels from a 70s truck. and the only other modification was the inner wheel wells were extended. is that correct? i appreciate the help with this. a lot of other threads left questions unanswered and wondering

[LONGHORN1962]

Basically it in a nutshell. Really not a bad swap, been wanting to do another just haven't had the time.

[72kool]

do you have any pictures of the trucks you have done by chance?? I love to see them

[LONGHORN1962]

No, unfortunately. Both looked similar to the maroon 4x4 and blue 68 in your photos. We only put fender guards on one, I just let them hang out on the other.