camarols1

iTrader: (17)

I searched some old threads, but I am curious as to what most of the
850+whp guys with OEM heads have run more recently with good results.
I am trying something different with my build and I found out recently(thanks Robin L and See5) that GM uses a HD 2.165 intake valve made of a "Silichrome" alloy for the LSA engines, and a 1.59 Inconel exhaust is standard on the LY6 engines.
I am thinking about the using new PRC EHT springs which have a little more installed and open pressure than the PRC Extremes.

Do you think the OE valves will hold up to the increased spring and cylinder pressures of a turbo build at this power level?
I am running the caddy lifters as well.
I have never heard of anyone breaking the stock LSx valves due to excessive spring pressure or HP, but it seems like an interesting question.
I am all about upgrading what is needed, but I could certainly use the money elsewhere in the build if the stock HD parts will suffice.

Any first hand experience would be appreciated.

Jim

black98ws6ta

iTrader: (77)

I have used the Patriot extremes and stock valves at 920 rwhp. Car was together for a full season and had no problems.

camarols1

iTrader: (17)

Thanks Anthony.

I saw your previous posts, but I wasn't sure if you had aftermarket heads or not.
This is a hobby for me, so if I am only making a handful of track days per year I am thinking that I will be ok with the HD valves from the general.

black98ws6ta

iTrader: (77)

Bone stock 317 heads with Patriot springs only.

camarols1

iTrader: (17)

That is awesome, nice job !!

BoOsT-CrAzY09

not too sure but check the specs against fererra or similar

camarols1

iTrader: (17)

Just found a set that Livernois sells.

150# on the seat @1.820
382# open at .620 lift
.660 max lift

These seem like they might be a better choice, since the lower spring rate will allow shimming them to increase seated pressure without having too much over the nose.

cjmatt

iTrader: (4)

are these there dual springs? I just installed a set. you shouldnt have to shim them, the kit comes with everything and is a pretty good price considering you get titanium retainers too. they are a bitch to install though without the crane or dogbone type spring installer, te regular c-clamp or screw type dont work too well on them

camarols1

iTrader: (17)

Those are the ones!

camarols1

iTrader: (17)

I just got the GM Inconel valves and they're a two-piece valve, and only the head is Inconel which is friction welded to a regular alloy stem.
Has anyone had success with a similar multipiece (LS3) design valve?
With the higher spring loads, I think I am leaning toward a one piece aftermarket.
Thoughts?

DeltaT

iTrader: (5)

A lot of this depends on your application. Drag racing does not put long enough periods of heat into the valve to warrant a change (for the HP ranges normal around here). But if you are going for long speed runs or road racing where you spend a lot of time under boost, then you need to start looking at valve upgrades, starting with the exhaust.

Jim

camarols1

iTrader: (17)

Thanks Jim,

I'm not planning any runs longer than a 1/4 mile, but my machine shop is concerned with higher spring pressures (180+seated/420+ open) and stock valves.
Especially the 2-piece GM inconel head exhaust valve, since it is inertia welded together.
The stock LS3 valves are hollow stem mulitpiece valves too, and I have not heard of a failure.