3/4 to 1/2 questions

[ltitsnw]

Hello...new to the board, been searching and reading alot, this looks like the place to come for answers..........I've got a 70 GMC 3/4 ton that I want to switch over to 5 lug......I have a set of 71 spindles, can I put 1/2 ton balljoints in my arms and will 1/2 ton springs fit in the front.........Question #2.......I've heard that all 1/2 ton rearends are the same from 70-87, outside to outside, what about spring perches(leaf) center to center, and are the leafs the same lenght as the 73-87's...........Another thought I had also, what about later model 6 lug stuff fitting, rearends and front brake components........a move to late model 6 lug opens alot of wheel choices........anyone have thoughts on converting from leaf to coil on the rear???.........Thanks Troy

[WB72]

Welcome aboard.

The change is not very complex. I went to a wrecker and got a whole front end (upper, lower A-Frames, spindles,Disks calipers and springs for $200 Canadain) It has all the components that you need for the front. Just make sure that the ball joints and brakes are still good.

As for the back end, my truck has coils, so I don't know about the perches, but I'm sure someone else has that info for you.

[69k5]

should be the same. nly diffrence is the one ton, i think 42.5 center to center on the perches. after 73 i dont know.

[Hooter]

It can be done, just some work, a cutting torch lots of penitrating lube and and an impact gun, you will get it done

[special70gmc]

the 1/2 ton springs will work but the lower a-arm will not take a 1/2 ton ball jiont like the upper will youll need new lower a-arms. good luck -kyle

[zenish]

i believe early classic makes a conversion spindle to convert from 3/4 to 1/2.

[ltitsnw]

Yes Early Classic's has a nice spindle that goes from C20 to 1/2ton 5lug, but I was not wanting to lower the truck right now because I haven't decided what to do with the rear yet, but I would like to get the front setup done and then just buy springs or a drop 72 spindle later once I've decided how to handle the rear. I think that I'm just going to put a mid-80's cross member under the front and play with the idea of switching the truck over to trailing arms for the rear and running a mid-80's rearend. I've got a real nice 67 SWB for it so it's getting shortened for that box, along with a 67 front clip. At the rate I'm going I should just sell it and find a 71-72 to cut up, this truck is a 80k rust free Arkansas truck that is all original right down to the hub caps. But I plan on using the body on my 4x4.....Thanks for the input..Troy

[Porkchop]

You can use a 73-79 front crossmember or an 80-87 front crossmember (i may be off a year or two on the year spans; someone will correct me). I think the 73-79 will bolt right up in place of your current cross member, but the 80-87 requires you to drill one hole, I think. I am going to put an 82 crossmember on my 69.

As for the rearend, I have been told you can swap in axles from a half ton five lug right into your 3/4 rear end, or you can put in a whole half ton rearend- the problem with this is that I think most half ton rearends were setup with coil springs instead of your 3/4 ton leafs. I have only seen one leaf sprung half ton rearend throughout my search. Also, I think in 73 and up truck rearends were made narrower and they won't work with 67-72's. I can't specify which ones, but some big car rearends are wide enough.

I may be off on some of this info, so please correct me if you know I am.

[zenish]

i think most gmc rearends are leaf spring.