bolt the leafs to the rearend and roll it under the truck
get it centered in the wheel well
measure a few different ways to make sure it is under there straight/square
and tack on the brackets
set the truck down and double check the measurements and how it looks
then finish welding it up
the shackle angle will also need some double checking, when the trucks weight is setting on it, before you finish welding


I really think it needs to be a little lower than it is in the pic :boxing:

 

I've done this. The 78 spring hangers mount in the outside of the frame stock. The 54 frame is wider, so there is not enough room on the outside, also the front hanger interferes with the running board mount. So, you have to mount the hangers on the inside of the frame. This means you have to box the frame where the hangers mount, so you have a place to bolt the hangers on.

You need the measurement between the hangers on the stock 78 frame. To locate them on the 54 frame, the hole in the 78 hanger in the rear lines up exactly with the hole in the 54 rear hanger, and the front hanger locates the same distance forward as it was in the 78 frame.

 

suspension fix

i have a friend who has a 49 truck and he sat a 454 on a 85 S10 frame and set his 49 on it he said it was'nt to much trouble to work it out he did it all by himself in his garage then added 2000 gmc leather heated seats and now has really nice truck best of luck to you

 

Howd you make out with the new rear end install? I did a similar install to my wifes 49. I used a ranger rearend that is 4.5 inches narrower. I had to box the frame and install on the inside. Be sure to measure the axel/ spindle and make them the same on both sides so the truck rides straight without wearing the tires unevenly. Im sand blasting in a week or so and will post a picure. Hope yours is going well.

 

wow this is good stuff. Im just about to redo my rear suspension on my 50 chevy, so how hard is it to box and mount the hangers? Im new at this building thing and this is my first project, do you have any pics?