I found a great deal and a full ls3 intake/fuel system and now trying to figure the heads out. Debating on some aftermarket 823's and others. I have a guy local to me that has a set of GMPP 823's with the high lift beehive springs/titanium retainers. Does anyone know what valves are in them? I can pick these up for around $500 but they still need rockers and pushrods. If they don't have the sodium valves should I source a set, find some rockers and pushrods and run them or just go with a set of 823's from one of the big name guys?

Id like to add that the Motor is lq4 and the heads are brand new and have been tapped for studs.

 

stock rockers with trunion upgrade is all you need.

as far as heads man, still what do you really want to spend?

Beehive springs suck, the price of duals has come way down and they are a worth while upgrade and peace of mind.

If you want a factory head, 243/799

If you want aftermarket and have $2,000+ to blow, AFR, TFS

 

I thought ls3 intake is rectangle port and 243's where cathedral

 

You are correct, they are.

If you can pickup a set local for 500 that are good with Titanium retainers I would go for it. The rectangle heads will make good power stock, for most builds there is no need to spend big money on aftermarket heads 90% of the time.

 

They are, but like in your other thread you dont seem to sure on what you really want.

Cathedral still gets my vote for heads, along with a fast intake.

If youre dead set on the ls3 stuff then id advise against heads that have been ported on the intake side. Flow numbers are one thing, but dont forget about velocity and runner size. The ls3 intake runner is already pretty big at 262cc (or was it 260?). Anyways, your budget will determine what youre gonna get.
Also, still either route you go id have a dual spring before a beehive anyday.

 

I was about 5min away from ordering a fast but I found an ls3 intake with fuel system for $250 so I figure id spend the extra cash I was gonna spend on a fast on a set of heads. With that said should I just pick up a set of stock l92's, have them polished and build up the drive train and call it a day? There isn't really a budget. I just don't want to spend unnecessary money if I don't have to.

 

Shooting for 450rwhp but 500 would make me happier

 

Youre not gonna hit 500 without some serious upgrades, ive got way better heads, and a lot more cubic inches and I hope to get around the 550 mark.

I dont think youre gonna do 500 with ls3 heads unless you flycut your pistons. The problem is the valve shrouding and limited ptv clearance.
They can still get you to your 450 mark, and a little more probably. If its gonna be ls3 heads than have a valve job done, maybe port the exhaust side some, and mill according to your ptv clearance.

 

I just did 454/425 with some tuning issues on a stock short block ls2 (fresh rings and hone, bearings, arp rod bolts etc)

Mods are full boltons minus ewp and thermostat
Stock ls3 intake that I lightly hand polished myself
92mm cable tb
Cnc ported Procomp ls3 heads
Custom FTI cam

I'm shooting for 480 rwhp when all said and done.

I wouldn't recommend cnc porting your heads though. The only reason mine are is because I plan on a 408 shortly and knew the extra .015 on each side of the valves from the boring would help flow and the cubes could use it.

With ls3 heads on a 4.00 bore the cam is CRITICAL

 

So what are some projected numbers with a 92mm TB/ls3 intake/fuel and a stock set of l92's with a tsp 228r 590/590 114lsa

 

That cam isnt made for ls3 heads at all, youre gonna have to change it.

Also note the difference between the ls3 and l92 heads are the hollow stem intake valves. Thats something you will want.

 

I would like to post an observation along with a little logic on the subject of LS cylinder heads, this somewhat goes right with my first comment above.

My observations on the LS based forums are (as much as I love you guys). Many not all, but many are simply "super bling aftermarket spend crazy" when it comes to cylinder heads. Haha. I have read though many threads (here and on other sites) where guys have spent good money on heads and are nowhere near using their potential. As I have posted before on other threads, the LS cylinder head design is a good one from the start and even in stock form posts up some respectable flow numbers and is capable of producing good power in comparison to many other engines.

Now for a touch of logic. This based upon some accepted formulas and thinking when it comes to cylinders heads. If we take some of these accepted formulas and apply them to the LS heads, we will find that a stock head could support more HP than many give it credit for. In an effort to keep this simplifed, I will keep this simple and basic. I fully understand that MANY MANY factors come into play in reguard to estimating final horse power numbers.

I am posting a few numbers relating cylinder head flow and possible horsepower potential, again this is generalized but gives an idea. We can take head flow and somewhat closely use it to calulate HP potential. These numbers reflect what could be obtained with a max effort project with everything right. Many today flow cylinder heads at 28 inches, so we will use this number to help us explore the hp potential of a given stock head. I will use flow numbers from the CarTech SA Designs book titled "GM LS-Series Cylinder Head Guide". It has heads listed with flow numbers, we can only *assume* that they were all tested evenly and the same and are accurate. Now I will take those numbers and apply a accepted formula to estimate the "horse power they could support" .

Numbers based from Head flow(at 28) X .257 X number of cylinders (8)

Casting--------Flow at .600-------Possible of supporting (flywheel)
241 LS1----------233------------------479 HP
317--------------253------------------520 HP
243/799----------260------------------535 HP

L92/LS3/LSA------326------------------670 HP

 

I hear so many different opinons about what cam/ heads work and dont.. I know everyone keeps telling me that my cam wont work with ls3 heads but i just got off the phone with TSP and they seem to think it would work fine and make plenty of power.

 

Itll work and be 'decent' but there are way better cams that were designed for 4.0 bore engines with ls3 heads.

 

Here, check this combo out

https://ls1tech.com/forums/dynamomet...486-447-a.html

 

Ll do more research on a cam, thanks. Say I go with a set of tsp 250cc heads what suggestions would you guys reccomend when going with rockers and pushrods?

 

If you go with the style head I have you need ls3 rockers (the intake is offset, the exhaust is the same) but with the trunion upgrade.
Also the hollow stem valve is worth the upgrade.

 

And idea where to get the truinon/rockers/pedestals? Any idea if my mounting bars are from the 317's will swap in?

 

The heads will come with new rocker stands you have to use. You can get some off ebay, junkyard, anywhere, just make sure they arent cracked or anything for the rockers themselves.

 

1.7:1?