Junk it or fix it? 89 c3500 rear suspension under my school bus Q's

[BBEEP]

Ok here goes: I am at my wits end with this. This project is a 1989 C3500 Chassis under my 1952 "White" School Bus. I had a shop in Portland do some work on the suspension and it just doesn't work.
I asked for the truck to be lowered about 6 inches. I asked for "helper" bags only, so that if I towed an enclosed trailer with 20 people I would be fine. I posted some pics.
When I got the truck back, it was a butt clenching ride home. A couple things, the rear swaybar was left off. The bags are rated 1500 lbs, one in front of the diff, one behind it, securely mounted to the frame on the top of the bag. The bottom of the bag was mounted to a bracket that merely surrounded the helper spring. By the time I got home, the rear bags had slide backwards at the spring mount 4+ inches!!
At first I connected a chain between the two lower brackets but have since made a bracket as you can see from the pic.
The problem is, it drives like a 52, swinging its ass-end as I drive down the road. IT SHOULD DRIVE LIKE AN 89!! HELP!
Should I junk it and buy a new Ride Tech or similar 4 link? or ???
And is the C-notch safe or too short?

[SCOTI]

Ride Tech has a slightly better tapered sleeve bag for HD AOL use (f9100's). They are rated @ ~2000# vs the f9000's ~1500# each.

What about ditching the overload spring @ the bottom of the leaf pack? That should help take some stiffness out of it.

If the 89 c3500 shock set-up is anything like my 90 c1500 after the flip kit, the shocks aren't doing anything to limit suspension oscillation during travel because they're compressed too much & @ a bad angle. I swapped to shorter shocks but the angle is still too much for them to 'work' well (& I even have Bell Techs shock extenders).

[NEWFISHER]

Agreed. How are the shock angle/ length and too many leafs in the system. Looks like the upper overload is still installed?

[TBONE1964]

I am climbing on board with this one. I have had a chance to meet the owner and was curious when I heard about this rig.

You will get it straightened out. You have to consider GVRW and tongue weight for your helper bag and spring pac rates. (20) 200 lb people = 4000 lb. With the right helper, you could loose some of the spring stack and use a heavy diameter sway bar for stability in corners. That would help the ride at Your shock angle should be considered at ride height. You will have to find a happy median between empty ride quality and loaded if the bus is going to do double duty.

Take care,
Tom

[PGSigns]

One thing I see that may be an issue is the C-notch. All yo have for frame now for 6 or 8 inches is a piece of 2" box tube. It is going to flex under load and will not carry the weight of a trailer. It may be flexing under the load of the springs. The helper bags need to go in the way they are done. The structure around them will not carry the load they are to help with. Can you get better pics of the shocks and the way the frame is done?
Jimmy