my 1989 chevy coil springs need replaced on my chassis p30

That is odd that you would have coil springs on the rear of the P30 chassis, unless they supplement the leaf springs.

My old 89 P30 chassis Winnebago was a tail dragger too and I fixed it by putting Hellwig helper springs on it and also a set of air bags and that fixed it.

The Air Bags helped a lot when towing my Desert Toys.

The local Truck spring shop was way more expensive and would not guarantee that what I told them to do was enough or to little.

Hellwig Helper Springs CLICK HERE

Air Lift air bags CLICK HERE