Can standard ls3 valves be used in ls9 heads using all of the ls3 valvetrain components. Im building a turbo motor and am using an ls9 block, I have a complete ls3 valve train with btr springs. Id like to use ls9 heads as they can be bought very reasonably bare and i'd rather not deal with the valve guide issues that go along with the titanium valves in stock form.

 

They are the same size, so they should interchange. I'm no expert though...

 

I know theyre the same diameter im just not sure about the overall length.

 

Call Ferrea.... But as it was said they should be the same.. don't think GM is paying extra for a different length valve in a Mast production head.

Or just look up the Ls9 valve length and compare.

 

Yes but the LS9 casting does not flow as well as the LS3 without porting. The LS9 casting has a hump in the port that needs to be cut out to match the stock flow of and LS3 casting which is why they are lower dollar. Might want to reconsider or invest in a good CNC porter. The GM LS3 CNC ported head package through Summit flows VERY well and is a fantastic deal, comes with the lightweight LS3 valves too. Not sure how much this will matter with a turbo set up but wanted to mention. It doesnt really seem a big issue with deck thickness and boost with stock castings ( deck thickness is the LS9 main advantage ) the four bolt heads are the achilles when wringing them right out

 

Grab used LS3 heads. Cheaper and makes more power. Then boost.

 

Well the problem when using the LS3 head (check with machine/LS shop) is that the LS9 block uses 12 mm head bolts versus the 11 mm head bolts that all other LS motor use. So have the machine shop drill them out. One question might be is what is the bolt head size and can you get a socket in the bolt pocket (say stock LS bolt head is 17 mm and now the 12 mm is 19 mm) or do you go with ARP stuff which can have small 12 sided heads. Have fun torqueing those on the car if you have some tough places I think they are like 110 pounds versus like 75 for the other LS motors.