F-350 Dually springs to F-250 4x4 interchange

averagef250 · Post by **averagef250** » Sun Apr 22, 2007 6:50 pm

I found a guy selling a Dana 70 from a '71 F-350 dually 10 foot or so frame truck. I have no use for the axle itself, but attached to it are the real beefy springs, overloads and U-bolt plates from the truck.

Now I know it would seam really extreme to want to put springs like these under my F-250 4x4, but I have a customer that has custom built rear springs under his 6BTA powered '86 F-350 dually 4x4 that make these old dually springs look weak and his truck rides great and doesn't have any issues no matter the tongue weight on it.

I'm pretty sure these old F-350 springs will be the right length and width to bolt under my '70 F-250 4x4, please correct me if I'm wrong. I would like to run them if they fit for two reasons: Better control with real heavy loads and also the springs are about 2" thicker than the F-250 stockers. With the 4" lift I'm running a 6" block in the rear with stock springs. I'm going to have axle wrap issues with the cummins, especially with 6" of block. I have a feeling these springs would allow me to run a 4" block and be stiff enough to keep axle wrap to a minimum. I wouldn't need to run any sort of traction arm setup.

The other thing I'm curious about is whether these springs are actually original. I've never owned an F-350 dually and never seen one that had rear springs and overloads this beefy, but can't say I've really paid attention to the duallies. If these are obviously not originals or look hacked up to you guys let me know. Thanks.

72hiboy4x4 · Post by **72hiboy4x4** » Sun Apr 22, 2007 8:28 pm

Hey Dustin,
I did exactly what you are planning. except I used the F-350 Dana 70 dually axle and the springs under my F-250.
All I had to do was get new U-bolts made to allow for the diameter of the Dana 70 and the length of the spring pack plus the 4" blocks. Even the U-joint was the same!
A few pics here. I can get more if you need 'em.

72hiboy4x4 · Post by **72hiboy4x4** » Sun Apr 22, 2007 8:33 pm

Oh, to actually answer your ??, they look like the ones in the second pic above. And they bolted right in. When I first installed the dually springs, I used the Dana 60. Had to get new U-bolts to match the length.
Make sure you get the frame stands for the overloads if you plan on using them.

averagef250 · Post by **averagef250** » Sun Apr 22, 2007 8:52 pm

Thanks a bunch. I think I'll make the drive out there and buy them. Got the brackets covered, the truck is a 7700 GVW model, it came with them. Those dually springs really look good on there!

I don't need the dually D70, the guy wants $350 for the axle, but he'll take $20 for the springs if I pull! The owner of the '86 dually with the beefed springs i mentioned above paid $1200 for his custom springpack. $20 works for me.

averagef250 · Post by **averagef250** » Mon Apr 23, 2007 3:58 pm

Went and pulled them this morning. They look the same as yours, 13 leaves in the main pack. I like the shock mounts too. They're real beefy and just stack under the U-bolt plate. I put a big spring pack next to a stocker and there doesn't appear to be as much arch to the thick one. Would you happen to know how much the ride height actually changed doing the spring swap? If it wasn't much, I might have the springs rebuilt and arched a bit more.

72hiboy4x4 · Post by **72hiboy4x4** » Mon Apr 23, 2007 8:03 pm

UUMM, I don't think mine changes at all by the time I finished with it all. I changed the springs a few months before I got the rear axle, But I don't remember a ride height difference either way.
I know its hard to tell ride height without a bed, but this is the best pic I have with the new springs and the dana 70 rear.

72hiboy4x4 · Post by **72hiboy4x4** » Mon Apr 23, 2007 8:09 pm

$350 for the axle?? I paid $100 for this..

Parted it out, sold stuff and still sold the hulk for $105. This was the donor for my Dana-70.

averagef250 · Post by **averagef250** » Mon Apr 23, 2007 8:25 pm

Thanks. I might have them arched some then. The guy is nuts thinking he'll get that much for that D70. To me the springs are worth more than the axle. Heck, I would have easily paid $20 just for the special dana 70 U-bolt plates and shock mounts. I earned them though. two of the U-bolts took me and a buddy both reefing on a 3' long 3/4" drive ratchet even with soaking in blaster. Thanks again for the pics and advice!

FLATBEDFORD · Post by **FLATBEDFORD** » Sat Apr 28, 2007 4:28 pm

Those look like mine too! My helpers are from an '80's F350. Bolted right on.