Stock intake vs performer?
The 340 'stock' Cast Iron Intake will outperform the Edelbrock Performer on Top End.
The Edelbrock Performer
Port Dimensions = .97" x 1.95"
The 'Performer' has tighter runner ports, and is better for the 1500 to 4500 RPM Range,
but not for 'high' RPM's.
In the Quarter-Mile, our 'stock' 340 Cast Iron Intake was a 'solid' {2/10's} quicker.