PRC's stage 2.5 LS6 Cylinder Heads come standard with the following options:
SEASONED GM 243 or 799 Cores
2.02"/1.575" Stainless Steel Valves
Your Choice of Spring Kit
Completely Assembled and Milled to your Specifications
58-64cc Chambers

All PRC cylinder heads are extensively researched and tested. The flow data below shows the superior performance of the PRC stage 2.5 LS6 cylinder heads!

Flow Data: 3.910" Flow Plate - No Exhaust Pipe
Lift Intake Flow Exhaust Flow
.200" 147 cfm 114 cfm
.300" 209 cfm 152 cfm
.400" 258 cfm 191 cfm
.500" 294 cfm 207 cfm
.600" 316 cfm 226 cfm

You also have the option to upgrade to the PAC .660" Lift Dual Valve Spring Kit. This spring kit is the top of the line and offers almost double the life of other valve spring kits on the market! The following items are included in the dual spring kit:
PAC .660"Lift Capable Dual Valve Springs
Precision-Machined Titanium Retainers
Hardened Machined Spring Seats
New Viton Valve Seals