making dually

I've never made a F350 into a dually but on the older Chevy trucks a dual wheel won't fit the axle is to short unless it's a cab and chassis. Cab and chassis frames are narrower than pickup frames. My old Chevy has dual wheel spacers on the axle then duals installed.

A standard 16x8 dually wheel dishes in 10" from the hub face. On a pickup this puts the tire and the inner fender well in the same place that's why dually pickups have a wider track than stake bed trucks. Stake beds use the same axle as a pickup. Dually pickups have a 6" longer axle. If you want to run the same tires on the front you'll need dually wheel spacers in the front also. Or the dually tire will be occupying the same space as your front suspension it'll work till you try and go around a corner. You can keep the stock wheels in the front. It's just meanes you'll need two differant spares. If your trailer spare is the same as the truck your ok

Years and years ago JC Whitney had kits to do that with everything in them. I don't even know if Whitney still exists or not but would be worth a look.

what ever you do, you'll hafta either cut out the inner wheel wells or cut out the outter fenders, normally the dually rear ends are shorter in width than the single wheel versions. any truck shop can get you the specs for the studs. I've always wanted to re-do one of my suburbans into a dually ever since I saw 2 of them in Omaha. maybe someday! i'm also sure you'll hafta move your springs and mounts too

well, the sheet metal is a nonproblem, it's pretty much rotted away, the bed has to come off and I was thinking of building a wood flat bed on it. replacement beds are simply too expensive.

looks like converting to a dually would be more expensive and/or complicated than I thought.

appreciate the help

Edited by LouSWPA - 07 Aug 2018 at 4:50pm

The front hub/bearing and brake rotor are the same dually vs single rear on a 4x4. The budd style wheel adapter is the only difference. The frames are different between a truck outfitted as a pickup from the factory vs a chassis cab unit. A dually rear ring gear is larger than a single wheel whether it's a Sterling, Ford, or Dana. As easy as a salvage dually axle would be to find, I wouldn't even think about some sort of mickey mouse adapters that won't give you any more weight capacity.

Actually on a GM all the frames are the same width. It's the width of the rear axle that varies. In fact I believe the industry standard is the same frame width for all brands. Otherwise aftermarket manufacturing of beds would be almost impossible.
DANA made more than just the 80 in dually versions. Had an 80 go bad in my '78 Chevy. Couldn't find one, ended putting in a 70. I believe they also made a lighter duty 60 in the dually configuration. There is also 2 different widths of dually rearends. Narrow is for cab chassis configuration, for flatbeds and utility boxes. The wider on is for pickups with factory OEM boxes so ad to maintain standard width between inner fenders and box rails.