CNC Worship: Inside Lingenfelter’s Ported 243/799 Cathedral Heads

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 lift, as well as lightweight titanium retainers, for our RPM goals. The advertised peak flow of the worked-over heads is a stout 320 cfm on the intake side and 224 cfm on the exhaust, at .600-inch of lift. That’s an increase of almost 32 percent, and should provide plenty of flow for our goals.

The dual-valvespring upgrade package adds springs capable of handling up to .660-inch of lift at the valve, as well as adding titanium retainers.

Performance Design Carbon Fiber Valve Covers

Of course, these amazing cylinder heads couldn’t be topped off by anything but the best. Sure, there are a variety of billet aluminum LS valve cover options out there, and they are pretty, but we wanted the crème of the crop — something that would really stop people in their tracks. We wanted carbon fiber. For that, we reached out to Performance Design, who is known largely for their line of Carbon R carbon fiber intake manifolds.

These valve covers are more than just eye candy. They aren’t some hydro-dipped aluminum piece that look like carbon. They aren’t valve covers with a carbon overlay. No, these valve covers are made entirely from 2×2 6K weave carbon fiber with a high-performance polymer seal flange, and uses titanium hardware for the absolute lightest valve cover design on the market with zero compromises made when it comes to strength.

Here you can see the robust yet lightweight construction of the Performance Design valve cover. The anodized billet aluminum coil brackets will fit LS3/LS7-style coils, and the injection-molded polymer gasket rail takes an OEM valve cover gasket. making for easit replacement from the local parts store, if needed.

The valve covers are made in several configurations, both with AN-12 oil fill ports and without (for dry-sump applications), and with or without LS3/7-style coil brackets (available in both black or red anodized finishes). For our build, we opted for AN-12 fill ports on both covers, not only to be able to add oil, but thanks to the use of universal AN thread, we will be able to easily thread in fittings for some vacuum pump testing we are planning on doing, as well as providing a convenient port to plumb in the blow-by gauge on the dyno.

The cover design has an undercut inboard wall for additional rocker clearance, retained mounting hardware, an integrated PCV port for street applications, and uses the OEM gasket, so you don’t need to hunt for anything special when doing maintenance. These valve covers are fit for a king, so they are right at home on top of these LPE cylinder heads. Not only will LS5.0’s performance turn heads, but its looks will also break a few necks as well.

Some of the awesome details of the Performance Design covers are the beautifully machined titanium mounting hardware (right) and the AN-12 fill ports with lightweight aluminum caps. We plan to use the ports for more than just oil.

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Greg Acosta

Greg has spent nineteen years and counting in automotive publishing, with most of his work having a very technical focus. Always interested in how things work, he enjoys sharing his passion for automotive technology with the reader.
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