[peterpar]

Ok, I will take a stab at answering this. The product ordering guides don't break the suspensions down to this degree, but they do give some clues to what you're asking about. The 235/55/16 tire was optional on the base coupes and convertibles and standard on the Z28. The 245/50/16 tires were optional on Z28s. The base Camaro's came with a firm ride and handling suspension and the Z28's came with a performance ride and handling suspension. If I had to guess, the 8TH and 9TH production number referred to above were base Camaros with the optional 235/55/16 tires and the 8TJ and 9TJ number refers to the Z28's with the optional 245/50/16 tires. You don't say which years the production numbers you list are from. This would differ between the model years I assume.