73-87 lift kit question

[aaront]

Some manufacturers show two kits, one for 73-76 and one for 77-87. But other manufacturers show only one kit for 73-87. What changed in '77?

[Engineer]

Size of the front u-bolts maybe?

There were a ton of changes all over the trucks from 1976 production to 1977 production, one of which was a heavier front axle housing on the 4x4 models.

Some lift kit manufacturers may just send u-bolts that fit both, whereas others send u-bolts that have an exact fit.

[NevadaNeal]

Thats the year Gm switched from the Dana 44 front to the 10 bolt.

[beastie_3]

but that doesnt matter as far as lifts go. axles almost identical.

[fitz]

I think it has to do with the size of the bolt & bushing size of the front spring shackle. GM changed the size of the bolt hole on the shackle at some point.  Some of the springs that say they fit 73-87 come with 2sets of bushings you can swap out to fit your truck.

[ehjorten]

Thats the year Gm switched from the Dana 44 front to the 10 bolt.

Really???...My '77 K20 has a D44 front.

[Irish_Alley]

Thats the year Gm switched from the Dana 44 front to the 10 bolt.

Really???...My '77 K20 has a D44 front.

Just cause your truck says its a 77 don't mean it was built in 77 think about nowadays when about fall you can buy a 2012. 

[ehjorten]

It has been a long-standing tradition that automobiles have a new model year starting in the 4th quarter of the preceeding year.  That is nothing new!

My '77 K20 has a VIN that says it is a 1977, was built in Janesville and was the 61,333 truck of the year.  My 1977 factory service manual also says that it has a D44.  If it was a K10 I think then it would have had a 10-bolt, but I would have to re-check my books.

Anyways...sorry to hijack the thread.

[beastie_3]

a D44 is available in 1/2 and 3/4 ton.

[Irish_Alley]

a D44 is available in 1/2 and 3/4 ton.

and so is the 10 bolt to 77+

[rugger]

i know this doesnt help you out much but i have a kit that was on a 75 k5 on my 85 gmc truck. everything fit like it was suspost to.

[aaront]

Comparing Procomp kits on Summit racing, the only difference is the front ubolts. It shows 73-76 with a 3" axle tube and the 77-87 with a 2.960" axle tube. Now, I know my 76 with a D44 has the second design tierod and the axle tube measures 2.960". I don't know if the front axle is original, because I know the rear isn't. The rear is a 12 bolt G80 3.73 and the front is D44 3.07. My plans are to put 3.73s in the front, 4 inch lift with 33's, and part-time the NP203.