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      Bare Heads Pair - Rectangle Intake Ports 276cc, 15 Degree Valve Angle
These are a direct replacement upgrade for rectangular port LS heads as found on LS3 L98 L77 L76 LS engines. They run standard valve dimension. So you can use your existing valves if they are serviceable. Having Bronze guides you will require spring bases to suit (with an ID of .565"). We have these available.
OE 4 Head Bolt Design 
Material | Aluminium 
Combustion Chamber Volume | 68cc 
Intake Runner Volume | 276cc 
Intake Port Size H x W | 2.585" X 1.275" 
Exhaust Runner Volume | 92cc 
Exhaust Port Size H x W | 1.467" X 1.614" D Shaped 
Intake Valve Size | 2.165" 
Exhaust Valve Size | 1.600" 
Valve Stem Diameter | 8.00mm 
Valve Length | Standard Length 
Valve Angle | 15 Degree 
Valve Guide Seal Diameter | 0.500" 
Valve Guide Material | Manganese Bronze 
Valve Spring Base Diameter | 1.250" 
Rocker Type | LS3 
Deck Thickness | 0.625" 
 
Flow Data @ 28"(CFM) With 2.165" & 1.600" Valves 
Intake 
@.300" = 213 
@.400" = 265 
@.500" = 296 
@.600" = 332 
@.700" = 338 
Exhaust 
@.300" = 152 
@.400" = 190 
@.500" = 210 
@.600" = 219 
@.700" = 228 
 
         
       
                      
                   
                      
                   
                      
                   
                      
                   
                      
                   
                      
                   
            
           
            
           
            
           
            
           
            
          