When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I purchased a set of heads off of a member here. He stated the heads were from a 2004 Z06:
I actually have a nice pair of 243's removed from an 04Z06... ( not truck heads). Untouched, approx. 45K miles...
UPS dropped off them off today. I removed an intake and exhaust valve to weigh and measure them to ascertain whether or not they really were "LS6 heads" (ie: the valves) or just regular 243s.
Can someone confirm the valve weights and lengths for factory LS6 valves?
Update: I talked to the seller this morning. As I expected, he bought these from someone else and was told they were LS6 heads. Needless to say, he felt cheated. I don't feel cheated because I fully expected that was the case. We squared up so I'll move on and figure out what I want to do. At this point I've got $500 in them and I don't see I can sell them without a loss. My original intent was to find a good set of LS6 heads and just run them and while it would be nice to have the light weight valves, I don't see paying for aftermarket hollow valves. It's a DD/weekend toy that lives 99.9% of it's life below 5000.
I blued a couple valves last night and they aren't contacting the seat fully, so they will at a minimum need a valve job. I have to decide how far I want to go with these. Local shops charge $500-$600 to do a valve job and deck the heads, while TSP offers a full CNC port and valve job for $799. So, ehhh.... decisions decisions...
Last edited by ChrisLSx; Mar 17, 2020 at 11:58 AM.
Many cars and trucks had 243 heads or 799 heads, which were identical, except the 799's finish because they were sand cast in Mexico. Some trucks even had a 243 on one side of the engine, and a 799 on the other. The heads had the same compression, port size/shape, valve size, everything. Some models that had them: Tahoes, C5 LS6, CTS-V LS6, GTO LS2, C6 LS2, Trailblazer SS LS2, etc
The light weight valves (hollow intake and sodium filled exhaust) were unique ONLY to 243's found on the 2002 through 2004 C5 Z06 and the 2004 through 2005 CTS-V. It has been said many times that the CTS-V had the light weight valves, and according to GM, the part numbers actually are the same. The 6K redline for the CTS-V might have had to do with the Z06 being Chevy's flagship, and more of a track focused car. The 5 less HP on the V was said to be from the exhaust manifolds, but I also hold my previous statement in thought about the flagship.
These lightweight valves along with better heat transfer, allowed the best high speed valve train stability. The Z06 had the highest revving engine of all the vehicles above, at 6500 RPM.
Last edited by 02torchred; Mar 17, 2020 at 04:01 AM.
I was always under the understanding that the light valves were exclusive to the same vehicles you listed. I can confirm that my '05 CTS-V has the sodium/hollow valves.
Last edited by Brackets; Mar 17, 2020 at 10:59 AM.
Not really an issue if you plan on doing head work. You can replace the valves with whatever valves you want. 243 castings are 243 castings.
I didn't plan to do head work, that's why I had hoped to get actual LS6 valves. It was supposed to be a budget upgrade (cam/head swap) in conjunction with replacing a leaking steering rack and factory crank balancer.
Last edited by ChrisLSx; Mar 17, 2020 at 11:46 AM.
Katech recently had a $500.00 port job special going on to save some money on your build.
They are still running it. But unless I'm mistaken, that's porting only. As I read it, the valve job is another $374 on top of that. So in the end, it's $874 to have them ported with a valve job.
LS6 head/Valve identification
