dually questions

[sluginxlt]

ive been thinking of making my 67 gmc 1/2 ton into a dually. im gonna be swaping out the whole front suspension for newer disc front setup anyways. is there a difference between c20-30 dually and non dually front end parts or is it just the wheels. and this may be a dumb question but same for the rear... is there a difference between a dually and non dually axle or again is it just the wheels. not forsure yet if im gonna do it, but this info will be something to have in mind when i go on my regular junkyard shopping sprees. hahaha. ill need to find some step side fenders for my bed too.

[sluginxlt]

also i plan on bagging the truck and "Z"ing and or sectioning engine crossmember, but is there drop spindles and tubular control arms for bags available for pre 88 duallies?

[The Big Green]

I'm wanting to do this to my 67. Maybe we can both get help on this subject. What I do know, frontend components on an uncles old 68 3/4 ton GMC. The frame, arms, and everything is the same, it has leafs, but I'm bagging so that doesn't matter. The rears are diferent between the single, and dually rears. I'm not doing stepside fender, there's a guy with a dually that's on a bed without fenders, and that's what I want, IF I can narrow a bit to tuck them. The 68 has drums in front or I'd use those, maybe the 71-72 were disc. I'm unclear on this but 71-72 had a disc 5lug though so maybe the 8lug was too.

[SCOTI]

A true dually uses a stronger & larger frame. You'd want @ least a 3/4 ton frame for starters. Crossmembers can be swapped over from the later years for front discs but the a-arms use larger (heavier duty) BJ's.

There's definitely a difference between the dually rear & the non-dually rear. But it's possible to swap a dually rear where a 3/4 ton rear rear was installed.

[The Big Green]

I myself are doing my swap for looks mainly. I'll use my 1/2 frame, because my heaviest load rating will be another 67sw. I may box my frame.

[sluginxlt]

yeah i plan on bagging my truck and hauling nothing but me and my passenger lol. i am also just after the look. and maybe very far down the road running semi wheels

[crazyredneck]

[QUOTE= I'm unclear on this but 71-72 had a disc 5lug though so maybe the 8lug was too.[/QUOTE]
yea my 72 3/4 ton has front discs

[The Big Green]

Cool, sounds like the same 71-87 8lug disc conversion as from 6 to 5 for us. Just and easy front disc 8lug and dually rearend for this swap.

[Tx Firefighter]

Here is what you have to know...

Duallys used drum front brakes through 1970, just like all of the trucks. In 71, GM went to disc brakes in the front. In 71-about 75, both 3/4 ton single wheel and 1 ton dually trucks used the same brakes, spindles, bearings, brake pads and calipers.

In 75 or so, GM greatly increased the size of the front dually brakes. From that point on, dually trucks used much larger brake components than the 3/4 tons did.

I recently did some dually swap stuff to a 72 model 3/4 ton truck I had. I got 86 model dually front spindles, rotors, calipers and all of that. It is remarkably larger than the early disc brake duallys had.

Shame you're not closer, I have the full 86 model setup in my shop that I'm not going to use. I even powdercoated the parts. I wound up selling the truck before I got the swap done.

[special-K]

The 1/2 & 3/4t frames are the same except for the rear cab mount perches.1t hubs use outboard spacers up front that mount the budd wheels out to compensate or the extreme backspace.1t cab & chassis rears are best for being only slightly wider outer wheel to outer wheel and require tubs to be fabbed due to narrower housing.