I'm really thinking of doing some engine mods to my '06 cts-v. Supercharger kits are way out of my reach and i would really like to stay NA. I really dont do any track driving and use my car as a Daily driver. Im trying to do sort of a budget build and it seems like the L92 heads w/ LS3 Intake manifold seems like the best bang4buck upgrade. I will also be getting a cam and some Kooks 1 7/8" LT's to be installed at the same time.

Just have a few questions...

1) So, only fully assembled L92 and/or LS3 Heads come with the better castings versus unassembled heads. I read that somewhere just couldnt remember...edited...found the link on page 17 of the LS3 & L92 info sticky
2) I plan to do a mild cam in my LS2, from my understanding, the LS3 Heads comes with better intake valves vs. the L92, but would i need to use the stock intake valves or should i just get aftermarket valves and buy the bare castings? (but then i loose out on the assembled worked ports if it is true). my cam will be spec'd for a DD car. I dont plan on going over 500rwhp but if its for better piece of mind, ill go with whatever. any other components worth upgrading (engine related)
3) with the LS3/L76 Intake, do I need to order it assembled or can i use my LS2 rail, injectors, TB?

 

No ls3 heads are ported
L92 have solid intake valves vs the ls3s hollow stem valves

If you have a choice, ls3 heads are the way to go.

You will need complete ls3/l76 intake assembly. Injectors, rails, throttle body

Pat G is a great person to spec you out a cam, and 500whp is very attainable with your setup. Consider milling your heads also for added compression!

 

Sorry I meant castings being finished...Here is the post from when i was researching i was referring to...page 17 of the LS3 &L92 info sticky

"I read somewhere that the bare heads are made from castings that don't flow quite as well as the casting being used in the assembeld heads. Does anyone have any info on this?"

"Yes, the bare heads are not finished like the assembled heads. You'll need to do clean up work and a good valve job on them to achieve the same results. And, as mentioned, the stock valves are a two piece design and should be replaced in a severe duty application"

Now, i obviously would get the assembled heads if i want to stay away from having to do any type of head machining. the assembled oem heads would do me good or is it worth the jump to the CNC ported heads for $750 each vs. $350 for the stock assembled heads. Im really trying to stay within budget.

are you positive about not being able to use my TB, FR, and Injectors from my LS2 IM onto the LS3 IM?

I was planning on using Pat G once I have all my mods planned out so he can tell me which is best

 

i have the L92 heads on my gto with the ls2 engine. actually i bought the last two cnc'd L92 heads that were available from gm performance parts. i do believe the cnc'd are still available from scoggin dickey though. and yes the Ls3 intake will need to be used. though i am sure you can use your LS2 throttlebody. also you need 8 rocker arms in the offset style for the L92 heads. and rocker arm pedastals for both heads. for head gaskets, get gaskets for the L92 heads NOT the regular LS2 gaskets.

 

Yes, keep your LS2 TB.

You can usually pick up a brand new take-off intake with fuel rail and injectors for $300

LS3 heads - 12629063 x2 - $629.90
LS3 head gasket - 12610046 x2 - $55.90
LS3 intake rockers - 12569167 x8 - $79.60
LS3 rocker stands - 12600936 x2 - $14.98
LS3 MAP sensor - 12591290 - $15.40 - (Ebay)

Shipping not included

 

You can keep your LS2 throttle body and fuel rails. All you'll need is LS3 injectors.

 

id jsut get the ls3 TB.. It is a little larger than the ls2 isnt it?

SDPC (scoggin dickey) has CNC heads for 740$ each. for the money thats a great deal, especially assembled with ls3 valves and dual springs!

 

Be careful trying to use a gold blade LS3 throttle body on an LS2 system. It may not work with it. I've done some reading on it & I read people having problems doing that swap. Engine shuts off, won't idle, etc. I have been told that the gold blade TB will work with my GMPP LS2 controller kit, but am skeptical, am not at the startup stage yet, so I cannot confirm/deny.

 

Dont forget the new PRC 250cc aftermarket casting ls3 heads. They have relocated valves for less shrouding on the smaller bores. Not to mention it has smaller runners than the stock GM head & flows like a ported LS3 head!

Without a doubt the PRC 250cc was specifically designed for applications like this. The relocated valves & smaller runners provide a huge advantage to the stock GM casting on LS2 & LS3 bores.

 

you know.. when i go to aftermarket heads on my pile... itll be yours. might i be bold enough to say theyll be able to out do TFS' vaporware ls3 heads..

 

Ive got a g8 with the l76 and it uses the entire ls3 top end...? Dunno why people would have trouble, gm did it no problem.

 

As far as I know both LS2 and LS3 are 90mm anyway. He might as well hang onto his LS2 TB.

But I have read a few times of people having problems getting the LS3 TB's working correctly. Something about the blade rotating the opposite direction??

 

Hmm didnt know of that. Dunno how the blade would go the wrong way either unless they installed it wrong

 

for a stock bottom end, and with a semi-agressive cam, whats your input on the LS3 Heads having too many CC volumes? looking at another members build on his cts-v, he has work done to his block too and with the LS3 Heads he made LESS power than a set of 235cc heads. I just dont want a dealer to say yeah, those heads are the best just to make a sale on a $2500+ setup, then im screwed for not researching so i just want to get it rite the first time

 

stock intake volume cc is 265cc I beleive, a lot for a small/moderate build. Thats why porting out the intake side on smaller motors *can* be a bad thing. You need a tight quench, and high velocity. unless of course you have a deep breathing motor that can take advantage of all that flow.

 

soi should steer away from the ls3 heads then huh. what volumes should I be looking at?

 

What are your power goals? Like Tainted said, if you're looking for around 500hp, a stock LS3 top end (heads, intake, ect.) at around $1000 total and a good cam is about the best bang for the buck around.

 

Looking for around 500-530 rwhp. Remember I daily drive the car and would do more "street runs" and Ive been doing alot of researching and it seems that the LS3 heads with the LS2 block are not too good for staying N/A and the ports are too big and doesnt make decent power until the mid-range to top end. Although, i can compensate that difference by running a bigger cam correct? It seems like the LS3 heads and intake seem like the best combo, and i can also sell my 243 heads for approx. $500 to offset the difference in price. Im only worried about the flow of the port size for the LS3 heads vs the LS2 heads and since i dont do no tracking, i wont really need that top end power. soo many options.

here is a good link that i saved from my research...

https://ls1tech.com/forums/generatio...-decision.html

 

Thats BS (part of it). You can make good mid range with ls3 heads. The whole key to the ls3 heads is correct valve timing. Search more, especially with Pat G. Theres a few specific ones in particular, one being an ls2/3 swapped rx7 speced by pat g that made 515rwhp. That was with untouched ls3 mind you.

Heres a link to another showing some great all over power in a mild set up tgrough cats even, AND using the l92 heads with heavy valves. Untouched as well.
https://ls1tech.com/forums/dynamomet...p-446rwtq.html