When it comes to OEM cylinder heads, the entire LS lineup of factory part numbers was a real advancement in the world of factory heads. You have an stock head with a large intake port, decently sized intake and exhaust valves, and overall, quality aluminum castings right off the production line — especially when compared to the LS’s spiritual predecessor.
One of the more coveted of the Gen-III/Gen-IV castings is the so-called 243 and 799 heads. With extremely minor differences between the two, as cores for aftermarket improvement, they are functionally identical. So when we were deciding on the core engine for our LS5.0 project, the Gen-IV LY2 got the nod thanks to its use of 799 cylinder heads.
We put the “cleaned up” (as much as possible with several different degreasers and a plastic abrasive pad) heads on the flow bench to confirm or bust the internet flow ratings. We were pleasantly surprised to see the stock 799 intake port flowing 243 cubic feet per minute at .600-inch of lift. Of course, that wasn’t enough flow for our goals with the LS5.0 project, so we immediately knew they would need some love. With that, we packed up our heads and shipped them off to Lingenfelter Performance Engineering (LPE).
Lingenfelter’s 243/799 CNC program opens the intake port (left) to 228cc and increases flow at .600-inch of lift to 320 cfm. The exhaust ports get opened up to 84cc, and the chambers stay at 65cc in the off-the-shelf configuration. However, for our needs, they brough the chambers down to 60cc.
Lingenfelter Ported 799 Heads
After they laughed at our packaging (a Coleman cooler is a perfectly valid shipping vessel) the team at Lingenfelter chucked them into the CNC and went to work. The first step was opening up the 210cc cathedral intake ports to a healthy 228cc, while optimizing the port shape as well. A similar machining treatment was given to the exhaust ports, adding 9cc of volume.
When it came to the chambers, normally LPE will clean them up on the CNC and then kiss the deck to keep the overall volume at the OEM 65cc. However, for our purposes, we needed 60cc chambers, so Lingenfelter took a little extra off the deck after working over the chambers. We opted for the valve upgrade, so the team machined the seats for Manley 2.02-inch stainless steel hollow intake valves and Manley 1.575-inch stainless steel exhaust valves.
Additionally, we opted for the dual valve spring upgrade as well, which gives us springs good for up to .660 inch of…
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