L92 "821" head on LQ4.

[SicMonte]

I have the oppertunity to buy 821 casting number heads brand new for very cheap...around $350 each. These heads will come with no valves and springs though. Are they worth it?

Are these heads the same ones as on a LS3? Since they are bare couldn't I just get the sodium filled valves and good springs and end up with a "LS3" head?


Another question....would a cam from a gen4 motor work in a gen3 motor?

My plan is to rebuild my LQ4 that I have now with the stock crank, rods and throw in a set of forged flat top pistons. I have a Comp cam that was meant for my buddy's L92 but didnt use. I wanted to put on the 821 heads and a stock L92 intake. What do you all think it will put out power wise? I know it depends on the cam but we sent it back to Comp to have it spec'd out.

Thanks for any info.

[WSSix]

I thought a pair of complete L92 heads was only like $1200 from GMPP? If that's the case, you'd only be saving yourself a small amount but it's still a savings. Sodium filled valves aren't worth the money in my opinion. Their advantages don't out weight the costs involved.

In general, the L92/LS3 heads are great heads to have. If you can get them for a good price, they are a good start and have plenty of room to grow. If money is kind of tight and the power goals are reasonable, LQ9 or LS6 heads will do very well for you also. They should come in less overall cost wise because you don't have to buy a new intake or intake rocker arms.

Gen 4 cam doesn't swap directly with Gen 3 engines. Keep the cam, block, and PCM the same generation. Unless you want VVT, Gen 4 doesn't offer an advantage over Gen 3.

[Ron in SoCal]

I Sodium filled valves aren't worth the money in my opinion. Their advantages don't out weight the costs involved.



Not sure I 100% agree w that. Anything that lightens up the valve train (and lives, these seem to) is a good thing.

Your advice on the LS3 heads is sound. Scroggin Dickey sells a CNC version for not much more as well.

[SicMonte]

well here's what I have.

a stock 214,000 mile LQ4

the above LQ4's complete front accessory set up

a stock L92 intake with fuel rails, injectors and throttle body

LQ4 wiring harness and computer.

hopes and dreams....

[WSSix]

Ron, it's purely a budget reason I don't recommend sodium filled valves right off the bat. They are superior but they aren't needed. Regular valves last a long time as well and the engines that run them perform just fine. LS2 heads are the same as LS6 heads but they don't have sodium filled valves.

Monte, I'd go for the L92 heads since you already have the other parts needed for the most part. You'll need an adapter to control the L92 throttle body or have your harness built with the correct connector. Same with the injector connectors. The stock GM offset rocker arms aren't expensive and work just fine. At this point, it'll only cost a little more to complete the conversion versus staying with a Gen 3 top end. The L92 stuff is superior so in the future you'll be able to expand your power production.

Go with 1-7/8 inch headers now unless you already have or find a great deal on 1-3/4 headers. I say this because you won't be giving up much going with the bigger headers now and they will support ported heads later.

Also, putting a 4in crank in the engine is cheap, easy, and when matched with the L92 heads will easily put 500hp to the wheels with great torque as well. That was the plan for my TA before I totaled my LT1 Formula. I'm still going back to that plan should putting turbos on the LT1 not work out.

[Mark Umfleet]

I just bought new 821 heads loaded with ls3 valves and springs from my local dealer for $345 apiece.

[214Chevy]

SicMonte, pm me bro. I can put you in contact with a guy that will sell you a pair of L92 heads loaded with the stock stuff for about the same price of what you're paying for an empty pair of heads. These are the #823 castings. At $350 each, that comes to $700. That's kind of steep for an empty pair. So, at that price, he will sell you a pair ready to go for around that same price. He will also, customize them to your liking if you want soduim filled valves, etc. I've bought two pair of heads from him. Let me know.

[Mark Umfleet]

Mine have the sodium filled valves. Their is a set on southeast MO Craigslist complete for $300. Their are a lot better deals out there. Almost always a set on ls1tech in the classifieds.