Edelbrock Victor Jr. LS3 Cylinder Heads # 61339 for 4 bolt flange, # 61349 for 6 bolt flange, via Marken Performance.  Edelbrock’s Victor Jr. LS3 cylinder heads are an all-new ground up design that incorporates subtle changes for improved flow and combustion. These changes were made to improve the limitations encountered in the stock cylinder heads when increasing the performance level of the engine. Changes include a 2.20" diameter intake valve with a canted configuration similar to what is utilized in the GM LT1 Gen V engine. The intake valve change along with the unique port shape produce almost 400cfm peak flow. These cylinder heads also feature fully CNC’d intake ports, combustion chambers and exhaust ports for consistency and improved performance. All of these changes make these cylinder heads capable of producing 600+ hp on an LS3 engine with stock rocker arms, intake manifold and exhaust manifolds. 

   It has a 69cc combustion chamber, 2.2” Intake valve diameter, 1.6” Exhaust valve diameter.      Video