630HP LS1 CNC Ported Cylinder Heads. 243 Cathedral Heads fits LS1 LS2 - Bare PAIR (2 Heads) Bare

• Factory Valve Guides 0.500" OD x 8mm stem. - see photo of checking tolerance. 
• Hard 355-T6 Aluminium - Race Quality.
• 3 Angle Valve Seats - machined - ready for assembly
• Deck thickness:  0.360"
• Intake Valve size:  2.00" factory size*
• Exhaust Valve size: 1.55"  factory size*
• Intake Port:  241cc
• Exhaust Port:  84cc
• Combustion Chamber:  66cc NOT CNC - As Cast Chamber. 
• *Note: Seats can accept the common aftermarket sizes of 2.02" intake and 1.570" (use Comp Cams part#: 6039-8 intake and 6048-8 Exhaust)

HP figures are "Potential" based on Flow/Velocity calculations* 

Lift          Intake         Exhaust

100          67                 66

200        144                107               

300        209                136            

400        253                154     

450        273                162    560hp

500        295                169    607hp

550        305                175    626hp

600        307                182    632hp

650         309               186    636hp                

Exceptional Quality for a Wow factor of a price! 

We can supply assembled using the below parts - click the links below:

• DRP Dual Valve Spring kit (PAC springs) - Proline RPM Series
• DRP Dual Valve Spring Kit (PAC springs) Street Line Series
• DRP Intake Valves 2.000"
• DRP Exhuast Valves 1.550"
• Supply Stainless Steel Valves