Just wanted to create a thread that might help some folks in the future determine what the difference are in the valves that come in the '02+ LS6 243 casting cylinder heads vs the '01 LS6/LS2 243 castings.

The hollow or sodium filled (exhaust valve only) that come in the '02+ LS6 243 cylinder heads are slightly longer than the solid valves that come in '01 LS6/LS2 243 heads. The battery in my digital calipers is dead, but it appears to be a few mm longer in overall length. I don't see any other way to tell the difference between the two without a scale (calibrated arm) or a known solid/hollow valve to compare overall length with. They look vitually identical to each other as far as I can tell. Hope it may help someone at some point....


Side by side. (hollow/sodium filled is on the left and the solid on the right in both pictures)
Intake


Exhaust


Solid intake weight in grams


Hollow intake in grams


Solid exhaust in grams


Sodium filled exhaust in grams

 

call thunder racing and ask for shane this guy is the best!

 

Excellent post, I am only replying in case your pictures disappear at some point in the future. I hate when you dig up an old post for info and the good stuff is in a now deleted pic or sig.

Your numbers:

Stock LS2/1 etc. solid valves --intake 100grams exhaust 88 grams
Stock LS6 lightweight valves --intake 74 grams exhaust 66 grams

GM numbers:

Stock LS2/1 etc. solid valves --intake 99 grams exhaust 86 grams
Stock LS6 lightweight valves --intake 76 grams exhaust 63 grams

GM numbers of course are with new valves with no carbon buildup or stem wear.

Lightweight LS6 valves are .6mm longer than solid LS valves.

The best LS6 resource:

http://www.idavette.net/hib/02ls6/


Larry

 

Hey all, thought I would update this thread. I bought a pair of 243 heads with the lightweight valves. Here's what I found when I weighed mine:

Hollow Intake = 74.0 g
Sodium Exhaust = 65.3 g

Hope this helps too!

 

And please correct me if I'm wrong, but doesn't GM give the lighter valves a 5 HP advantage in their ratings of LS6 motors? The C5 LS6 was rated at 405 HP with the lighter valves, but the CTS-V LS6 was rated at 400 HP because it had standard valves and I believe the valves are the only difference in these 2 motors, correct?

 

^^ No, the CTS-V LS6 has the same valves as the C5 Z06 LS6.
The 5 hp difference for the C5 Z06 is either the exhaust system(less restrictive) or the intake box(better air flow)