KCS

iTrader: (20)

FWIW, the LS3 intake valve also has less margin on the head diameter, so you gain about .5cc of combustion chamber volume compared to L92 valves.

01CamaroSSTx

iTrader: (3)

Interesting....So now I have a slightly larger combustion chamber and a little loss of compression. Are the 823's and 821's 68cc or 70cc?

01CamaroSSTx

iTrader: (3)

Found this on the forum: LS3 intake valve stem length/height.

I have a sent of Lunati High RPM lifters that I plan to run in this motor. It calls for .035-.040 preload and am thinking I should run different length pushrods or adjustable rockers.

G Atsma

.5cc is NOT worth worrying about....

bortous

I was running stock LS3 valves for years. Never had any issues.
If I needed to get valves I would not get GM valves.
The Manley race master solid stainless are a superior piece with a better valve angle which means more flow.
Finding a good machine shop to cut the seats apparently is a very thing to do and picks up some power.

FormulaBoat

iTrader: (1)

For longevity, I’d trust stock GM valves over aftermarket. I assembled my L92 heads with new stock GM stainless intake valves from the LSA, and stock GM inconel exhaust valves from the LY6. Going in front of an A6 trans, so won’t rev past 6k.

There is always lighter, but I’m going for +100k mile durability, and if I pressurize it later, then I know the valves are ready.

bortous

This is partially true however the stock LS7 valves have been known to fail and also in the LS9.
Not sure about the LSA engine though.
Manley or Ferrea are stronger.
The solid stainless stainless would be the most durable.
But if you are running crazy boost, you may even need the high end exhaust valves so they can live