Lowered '57 Pontiac Star Chief - pinion head hitting bump stop

[KiwiStarChief]

I have an issue with my 1957 Pontiac Star Chief. When I got it, it had dearched rear springs, 2" lowering blocks, and load leveler rear shocks (with a coil spring).

As it was riding a bit harsh, I replaced both front and rear shocks (front suspension is a front clip from an '78 Malibu). Front worked out OK, but the rear shocks were replaced with Gabriel 82156 Heavy Duty Classic gas units. These have an extended length of 20.23", and a collapsed length of 12.37". Unfortunately these shocks lowered the car by a further inch & a half, which was too low. I have now adjusted the ride height by replacing the blocks with smaller ones, and the height is back to where it was.

My issue is that when hitting a bump in the road, the pinion head is hitting the bump stop with a thump. I tried shortening the stop by 1", but it is still hitting, so I assume the shocks are not as hard as the load levelers, allowing this to happen.

Should I just remove the pinion bump stop, or are the shocks the wrong working length for my lowered car? I also note that there are no rear axle bump stops fitted, so a previous owner has removed them for some reason.

I would greatly appreciate any advice or suggestions you may have to resolve this problem.

[dhutton]

Conventional shocks do not affect ride height. They merely dampen the suspension. You likely need stiffer springs to compensate for the loss of springs on the load leveler shocks.

Don

[MonzaRacer]

Your dearched springs are too soft. Most likely they simply removed leafs.
To stiffen up the rear leafs try finding a thick wall pipe the same diameter or just tick under width of the spring. Have it cut in half. For length you want 1/2 to 3/4 of the length from axle housing to the front spring eye. Then have a 1/4 hot or cold rolled plate with two or three tab legs wider that spring and large enough to allow square end ubolts to clamp to the spring or a flat plate can be used.
Spring clamp this to the leaf. Effectively this will eliminate spring wrap which is most likely what you are getting and it will stiffen the spring a bit making rear of spring do its job better.
IF you can extend clamp plate under diff ubolts/clamp plate it helps also.
Ill have to dig up my photos of what might help.
Cool part id you can shorten it up to help soften the ride a bit.
Or just do this and add Ridetech shock waves and do away with rear of leaf spring all together!
Or even add a load leveling system like Ridetech and Firestone sells. But spring wrap and weak springs let back end drop as rearend twists.