79 F350 4x4 Axles in a 71 Highboy

[71PA_Highboy]

All,

I found a 79 F350 4x4 with D60 and D70... can I swap these axles under my bump EASILY?

I have heard that the high pinion D60 will cause issues with the front crossmember on the bump when wheeling, but I don't plan on wheeling it hard...

Any input would be appreciated.

Thanks!

Eric

[averagef250]

You can't fit long tube headers on an FE truck without a lift if you run a HP axle. Other than the header clearance issue everything else is pretty straightforward. You'll have to cut off the passenger side lower shock mount and flip it to the rear of the axle and you'll want to swap in the disc brake proportioning valve. You'll have to cut a few inches out of your front driveline as well. An early highboy sits 3-4" higher than a 77.5-79 truck so the brake lines on the newer trucks are shorter. 76-77 disc brake hoses are really expensive so I've found if I ask for 1990 F-350 4x4 hoses they bolt in with minor bending and cost 1/4 the price. They are alot longer too. For a 4" lift you can also buy F-450 or 550 4x4 hoses.

The 78-79 dana 70's use about a 6" wider spring perch spacing than the earlier F-350 2wd's and highboys. You'll have to cut off and relocate the spring perches. A dana 70's pinion is an inch longer than a 60, you may get away without shortening the rear driveline, but it would be best to have it the right length. You'll also have to cut the little ears off the stock highboy 4" rear blocks so the U-bolts can spread wider to go around the Dana 70 axle tubes. You can have new round U-bolts made at a spring shop or you can find lower axle plates that will fit the big 70 tubes. I found the easiest ones to find are under 70's 1 ton chevies with a 14 bolt or dana 70. The dana 70 also uses a 1350 series pinion yoke. You can put your 1310/1330 dana 60 yoke on the 70 or you can run an adapter U-joint.

[71PA_Highboy]

Looks like the Rear is a 60.... Oh well... Now I will have the fine spline axles...

As a side note, anyone want to trade a RUST FREE cab for a pair of 79 F350 Axles?

TIA,

Eric

[averagef250]

I've got a very clean '69 F-250 4x4 cab. I'd rate it a 9.5 for rust. Perfect cab mounts, maybe a few pinholes in the floorpans and some very minor bubbling in the door jamb below the passenger drip rail. Other than that, it has one 3/4" hole from a CB antenna in the roof and it had factory cab marker lights, somebody welded the holes up, but the wiring is still there.

I wonder how bad shipping would be.