Does a 350 from 90 Sierra Z71 have hydraulic or solid roller lifters?

The 1990 GMC Sierra 1500 Z71 with a 350 (likely a 5.7L small-block Chevy) used hydraulic roller lifters. Solid roller lifters were not standard equipment on production vehicles of that era. Solid roller lifters are generally found in high-performance engines that require more precise valve control and are typically aftermarket modifications.