Besides the engine displacment and the 9bolt rear is there any difference in spring rate sway bars etc? I may be buying a 5.0 replacement for my stolen and totalled 5.7 88

depends, 5.7's came with oil coolers etc, they mite have higher spring rates depending on packages and also the 5.7's had the most beefy stuff they had at that time, the 9 bolt/700r4s and the sway bars/rear disks etc.

I have owned my '87 5.7 liter IROCZ since it was brand new. The 5.7L IROCZ cars had to have the oil cooler, 9 bolt rear end, 4 wheels disc brakes, and the 700R4 tranny. The 5.0 cars came with the 10 bolt rear and could be purchased with either the 700R4 or the weak 5 speed.
I dont know if this helped you any.