Show off.DJWorm said:There were 2 options to consider when going to the 427 LS7 to quench it's need for higher flow rates
1. Engineer the 3v head which is more complicated than the 2v head with more moving parts, increased weight, a slave rocker arm etc.
2. Or reengineer the C5R head for production use.
Both concepts produced about the same flow and HP and torque ratings. However the C5R head design was a proven, winning entity. The reengineered LS7 head based on the C5R design had the intake port volume and flow and by mearly increasing the combustion chamber size and the exhaust port volume made it suitable for a production, smog controlled, slightly detuned (as opposed to a full race tune) engine. The LS7 did gain even more efficient from the 3v by offsetting the rocker arm to allow an even larger intake valve.