LS1 chamber.

LS1 intake ports. All except L92 and LS7 feature cathedral style intake ports.

Cathedral intake ports measure approximately 3 1/8" in height.

Cathedral intake ports measure approximately 1" in width.

Exhaust ports are D-shaped.

The LS6 heads feature a casting number of 243.

A view of LS6 intake ports.

Heads feature pushrod clearance reliefs.

The LS7 heads feature casting No. 8452.

Full view of LS7 rectangular intake ports.

Ported LS7 intake ports.

All Gen III/IV heads feature beehive-style single valve springs and small retainers.

Beehive springs take advantage of coil shape to minimize unwanted harmonics, eliminating the need for dual damper springs.

LS1 and LS6 heads require a rail for rocker mounting. The mounting bosses in the head casting are machined flat to accept this rail.

The LS7 needs no rail. Pedestals are machined with a female radius for paired-up rocker shafts.

LS7 intake rockers feature an offset.

In some applications, exhaust valves are hollow with sodium. photo courtesy Katech

Roller lifters are registered to prevent rotation in lightweight composite lifter trays.

Each lifter tray holds four lifters. The tray is secured in place to the head with a center bolt.

Camshafts are unique to the Gen III/IV engines. (photo courtesy Katech)

Here's a close-up of a CNC ported combustion chamber on an LS6 head. (photo courtesy Katech)

Katech's "Street Attack" 7.0L LS7. (photo courtesy Katech)

Katech's LS7 crate engine. (photo courtesy Katech)

LS6 equipped with a supercharger. (photo courtesy Katech)

All Gen III/IV engines feature individual ignition coil packs. (photo courtesy Katech)