My '78 F-250 is great for hauling with the leaf spring rear and factory overload helpers. But the ride quality needs help.
I'm curious if anyone here has upgraded to a multi-link (aka. 4-link) rear setup. I've seen some kits in my searches, but need to hear your positive/negative thoughts.
Do I need to spend the extra cash for HEIM joints or does the rebuildable enduro/johnny joint work fine too?
I'm sure coil-overs will be fine. Maybe adding air bags to lower the rear end for loading/unloading sounds cool too.
Anything I should consider with a DIY kit?

 

Whether you get a kit or piece everything together you need, there is going to be quite a bit of fabrication involved converting to a link setup.

Do you plan on towing with your rig or is it just going to be a toy?

If you still want to tow with it, you might consider swapping in a suspension from an '05-'16 Superduty. The ride will be a little better (my '11 F350 rides better than my '79 F150) and you will still be able to tow heavy loads with it.

Not saying you can't tow heavy with a link suspension, but the kits that are available are more for off-road flexibility. Building a link suspension to handle heavy loads will be a different set up with shorter link bars and less flexibility.

With a short link set up you can use regular coils and shocks and you would have a similar setup to modern Dodge 2500 trucks. Coil-overs would work, but I don't think you'll be able to find coil-overs with a heavy enough spring rate unless you go full custom which means $$$$.

Regardless of heim joint style they are prone to wear quickly if you don't keep them clean.

You could keep things real simple though and stick with what you have and put a fully loaded tool box and a spare fuel tank in the bed of the truck so you have some ballast weight in the back. I know when I have had my 1000# Harley loaded in the back of my F350 the ride improves a lot. Add some quality shocks and some air bags for when you tow and you might see a big improvement and zero fabrication to speak of.

Another simple thing that might help is take your current leaf packs off, disassemble and get them cleaned up and painted. When you reassemble put some graphite between the leaves so they slip past each other more easily. That combined with fresh hardware, bushings and hangers that move freely might improve riding quality dramatically.

That said, it's still a heavy pickup meant to tow heavy loads and they are going to ride stiff.

 

I plan to still haul loads in the bed and tow. Maybe get a camper some day. The ride isn't terrible. It's been a minute since I drove this gal around town, but I want to say it and my former '17 KR SD CC 4x4 6.7 are fairly comparable. I'll get re-acquainted late this Spring if I reinstall the leaf packs (that's my 'hopefully almost on the road' date). I rebuilt the '78 back in '94 and did as you suggested to the springs. After all this time, they'll need a freshening up and replacing the rear hanger bushings - which are frozen.
My '78 frame is fully stripped with exception to the main cross members and is heading to blast and paint on Monday. So I'm just fishing at the moment with no commitment...
I hear ya on loading the bed to improve the ride. Maybe I'll attempt to keep my dual tanks full, which will be near impossible with a 460. But a 6R80 tranny and EFI should help.