LS9Drew

Which place would be the best place to get Heads for my Z? Katech, livernois, wcch, etc?
And what parts should I get for extra security. I don't have an issue or anything right now but I planned on doing heads anyways in the future and want to get a ballpark on how much to save.

Should I port them, deck them, etc? I'm on 91


Mod plans for this car is just intake, headers, ported intake or fast 102, heads, ported tb, katech clutch from richierich, and tune. Really aren't planning on a cam but down the line I might change my mind and do a baby cam. I want to make this a "sleeper" and stock like drive ability


Thanks

StreetRacingGuy

If your not going to do a cam don't do anything to the heads other than deck them to get higher CR. However, since your running 91 ocatane I would leave the heads alone...other than better valves/guides for safety margin. Heads flow great as is, only need to do them if your doing a cam. If your going to mod it without doing heads, I dont know how much extra power your going to get with headers/intake/tb t be honest.

Unreal

Decked them can be worth a solid 20-30rwhp.

WCCH, Advanced Induction, Texas Speed, LPE, etc etc. There are plenty of good options. WCCH seems to be the goto place. I did Texas Speed heads that should be here today after a nice 6 week wait.

LS9Drew

I just figured if they are going to be off I mine as well port them unless you don't think its worth the money even though they are off.

Can I deck them on 91 safely?

Should I upgrade the rocker arms, lifters, valve springs, pushrods, etc also?

Unreal

If you deck them you need new pushrods. Rocker arms, valve springs can always be added later with the heads on the car. I would only upgrade that stuff with a cam later. Get sprigns/etc that go with the cam. Stock ls7 lifters are good. Friend made 578rwhp on 91 octane with his heads decked .030" and a Lethal Cam.

LS9Drew

So the rocker arms are no issue on this car? I know 07s had issues but I have the 241st 06 made so Idk if I am prone to that issue as well.
Would there be an issue putting in better springs while they are off to save money on install in the future if I do a cam?

LS9Drew

578whp on 91 is really good I bet it rips.

I'm only shooting for like 510-520whp anymore I just think traction would prolly just be too much of an issue on my street tire nt05s

SS MPSTR

Traction is an issue with just exhaust and a tune

I'm sending mine to AI for decking, CNC port work and guides/valve job. It should be good for 590+rwhp with my small cam, LSXR intake, headers/exhaust, Hallech and a re-tune.

Unreal

No reason to upgrade the springs and put more wear/tear/etc on the valve train when you are running a stock cam. I would just do it all at once. Do a small cam, heads, springs, etc all at once.

LS9Drew

Ok gotcha, so if I just stick to the stock cam just deck the heads, valves, valve guides, and maybe port work?
That will prevent all possible failures right

Michael_D

You can reach your power goals without any head work and a mild cam. I'm right at 525 with a QM550 cam, K/N, headers and a ported intake. With traction control off, I have trouble with traction in 2nd and I'm running NT05's.

I intend to send my heads out this winter, but my goal is not high peak power. I want better throttle response throughout the rpm range and I do not want to loose off idle drivability. It sounds like that is what you are looking for as well. I also want to put my mind at ease and check clearances. But if I'm going to go through the effort of pulling the heads and checking clearances, I might as well send them out and have them rebuilt.

If you have them milled, I would not go over 11.4 static cr with your fuel (my premium is 90, and I probably will stick to 11). Increasing compression does no good if you have to pull timing to avoid detonation.

There are numerous head porter's around. Be careful picking one. Make sure they offer CNC port work. Hand porting is a lost art and there are not many who can get all the ports to flow constantly. CNC with some light hand blending is best way to go. Also, I would shy away from any port work that increases the intake port size, considering what your goals are. You loose velocity with larger ports and the OEM ports are plenty large enough. WCCH, AI and LPE all offer CNC port work where the intake port remains the same size. They have, through their own experimenting, developed profiles to increase flow without lowering velocity.

I've probably spoke to no less than ten different shops that specialize in LS7 builds. Every single one of them has recommended to stick with the OEM rockers. Even though I have a strong preference for roller tip rockers, I'm inclined to listen to these folks. Some have recommended upgrading the trunnion, some say to leave them be (unless they are early year rockers, then they suggest to buy new OEM or upgrade the trunnion).

Depending on the cam you eventually go with, you may be fine with the OEM springs. If you increase lift, you'll need to change them. You have many choices available for this, but the total lift, valve weight and rpm will dictate springs to use.

OEM lifters are quite good and there really is no need to swap them out. They are light and reliable.

Pushrods may need to be changed, depending on if you mill the heads or swap out the cam. This is something that needs to be checked after the heads are installed to ensure you get the correct length. Don't guess on this, take the time to check them correctly.

The OEM guides are fine. The clearances should be checked though. If they are out of spec, then the option is to replace them or install guide liners. I'd replace them verses liners(but that's just my personal preference). The only option for aftermarket guides is bronze, which is why you hear about bronze, it has nothing to do with being "better". Some folks call bronze "self lubricating". This is not entirely accurate. There are some bronze alloys that are self lubricating, but that is a different animal as they tend to be oil impregnated sintered low speed bearings or sleeves. This is a pretty lengthy topic in itself, but the short version is that some bronze guides have increased oil retention due to the alloy's porosity, so it could be argued that they have better lubricating properties. The most preferred guide bronze alloy is Manganese Silicon Aluminum. Not all shops go with this alloy as it's difficult to machine requiring diamond cutting tools.

Generally speaking, when you are after good performance throughout the rpm range, in a perfect world you would want very high lift with minimal duration and overlap. Unfortunately, there are always sacrifices to be made with push rod actuated overhead valved IC engines. As lift is increased, more stress is applied to the valve train, so there are practical limits to consider. I really like the specs of the LPE GT19, as it has mild duration and overlap, but I'm a bit concerned that it may have too much lift for extended reliability. A lower lift cam with more duration will yield good mid range - top end performance, but at the sacrifice of low rpm performance due to the increased overlap and reversion. A slight (20-40deg) back cut on the combustion side of the intake will help reduce reverse flow, but only if there is enough thickness. I generally leave camshaft selection to the folks who make them and use a spin tron to help model the profile. Be wary of folks who sell "custom grind" cam shafts. More often than not, they are simply guessing. Without a spin tron analysis, there's no way to validate or verify valve train stability and harmonics.

LS9Drew

Wow thanks Michael lot of information to take it, any idea how much a typical valve/valve guide job cost with some porting?
I guess I don't have to worry about the rockers since I have a very early 06. If I stick to stock cr ratio should I put in new oem pushrods or replace any other part with oem parts if I use the stock cam?


Ya I haven't overlooked livernois they have made some great numbers with h/c packages

Mopar Jimmy

Katech, WCCH or Livernois.

If you talk to Jason at Katech and tell him you ALSO want to take preventive measure for the heads to be relibable, I would certainly do as he suggests which most likely would be to upgrade to bronze valve guides, do a valve job, keep the stock TI valves, and if your keeping the stock cam put on some stock C6 Z springs.

Of course have him or anyone else do their other go fast stuff like milling the heads, porting, etc., but I would DEFINITELY take the aforementioned preventive measures to plays things safe and have GOOD piece of mind!

LS9Drew

Ya I will all of those places seem to know what they are doing so I'd follow what they suggest. Any idea how much something like this would cost just?

I appreciate the help everyone.
Maybe Katech, Livernois, or WCCH will chime in here with some opinions

blackvetterzo6

You surely dont need to rip your engine apart for 510-520 RWHP. Everyone is talking reliability of the ls7, even myself. The blown engine threads have really taken off. Now your gonna see a shitload of head work threads. good luck with the rebuild.

KLRBEE2

^^^I agree; you beat me to it. I know everyone is talking about safety measures for the heads, which is good if they're off the car already; however, the power level you're trying to achieve can be had with just bolt ons and a tune. On my 08, I have a VR air intake, FAST LSXR intake manifold non-ported, LS3 fuel rails with stock injectors, ported and polished stock throtle body, AR 1 7/8 LT headers catless and X-pipe, and 160* thermostat, and of course, a great tune...she dynoed 525 but was kept at 513 with an A/F ratio of 12:1. Good luck and enjoy that bad boy!!

LS9Drew

my car isnt down lol, nor do I think i need to take the heads off to make 510-520whp I would just be doing the heads for added power, security, and ease of passing CA smog sniffer test

Those are some good numbers, how did you like the gains on the Fast 102? Is it worth the $1000 on just bolt ons?

KLRBEE2

I love the power and absolute great response. I have a friend (forum member ANGRYZ) that has the same mods, except for the intake and different tuner. His makes 485rwhp. A lot has to do with the tune, but I would say realistically, it nets a good 20-25rwhp.

You can buy them new for around $850-860.

LS9Drew

What about over a ported stocker? Its double the price so Im still deciding if thats the route I want to take. I know it'd be over $1000 since I'd want it shaved/painted to not be noticeable

KLRBEE2

Ah, then it's going to cost you more...there's a vendor here, if memory serves me, that sells them that way. As far as the stocker being ported, I don't have any personal experience; however, from reviews I've read on this forum...it's a waste of money and no significant data to support any gains.