New leaf springs to help ride???

What do you have?
Daycab?
Coffin sleeper?
Tractor?
Straight Truck?
Mis-matched tires?
Long w/b or short w/b?
Ride better loaded vs mt?

 

Steering arm,out of balance tires

 

Worn cab shocks or air springs.

 

What suspension? If its low air leaf then something is definitely wrong, if it's air trac, or whatever the equivalent to that was in 93, its kinda how they ride. If it is air trac, there is hard plastic or umhw pads you can put between the spring and the suspension wear pads that greatly reduce the spring bouncing around in the back and slapping that wear pad which is directly connected to the frame which means you feel that spring slapping up. I installed those on my rear suspension and it improved the ride from the rear suspension 1000% especially when you were light over the drives. If your front springs are worn, which they probably are if you already replaced the bushings then new springs and better shocks will clear that up.

 

Everything they have suggested here is good, I just wanted to add. Check your cab mounts, grab a pry bar and pry up and down. They are easy to replace and a big difference when done.

 

I was looking into Liteflex composite leaf for my 379 a while back. Never finished my research but, from what I understand they are much lighter than a steel spring and react much faster creating a smoother ride.

A side note. I did swap out steel leafs in my 67 camaro for Flex-Form composite leaf and have not yet had the opportunity to put them through their paces but, I nearly doubled my spring rate for axle control and a firmer feel in the rear and the manufacturer said the ride will still be light years better than steel. He also said the biggest benefits of composites are being able to increase spring rate and still end up with a better ride and they never lose their spring rate like steel. They also weigh a lot less, For example, The car had Z28 leafs and Calvert Racing traction bars that were replaced with the composite leaf (8 lbs each) for a total weight loss of 78 lbs. I imagine the weight loss on a 379 would be tremendous.

It's worth looking into if your searching for a better ride. I believe Volvo tractors are factory supplied with composite leaf up front.

 

If it is on the front the upper shackle pin can wear up into the aluminum hanger. When that gets bad enough that does not help the ride at all. While uncommon the bushing and pin in the front of the steer axle spring can wear out. That will allow the front axle to wander back and forth under the frame on rough roads. Hell to drive in curves with pot holes.