If you're looking at Gen 1 SBC, passenger cars from '87 on were roller lifters, one piece rear main which is what you want. If you're looking at trucks, vans & SUV's they retained flat tappet cams through '95, but they had one piece rear mains so they can fake you out. You want roller lifters. Here's a pretty good article for basic information - Chevy Small Block - Car Craft Magazine Pay attention to the section "Roller Warning" regarding cam selection. Glenn or Tech can help with which OEM heads are best, but a set of aluminum heads can be pretty competitive in price if you're having the iron heads re-built by a good shop.