other than the valve covers, what are the differences between the heads on a 98 LS1 compared to the other years (up to 2002)? I recently picked up a set of 98 heads to get ported and polished but am now having second thoughts if the money spent would be worth the gains that i would see. The heads would be going on a 2000 with the mods listed below and eventually a cam package (not sure about which one yet). Any info would be great!

 

The heads are pretty much the same with the main difference being the bolts. 98 are perimeter bolt and 99+ are centerbolt. Also the coil packs mount differently to the valvecovers. Each individual coil pack is bolted to the valve cover on 98's, for 99+ each coil pack is mounted to a coil pack bracket and that bracket bolts to the valvecover. And I think the PCV system is slightly different as well, but not enough to make that much of a difference.

I switched from 98 to 99+ heads. I would not go back to 98 style heads. JMO