FLYNAVY30

iTrader: (1)

I finally assembled all of the other required items for the head upgrade so Im looking to order heads sometime this week and Im looking for input/opinions.

The car is a 2003 Z06 with a FAST 90/90, Long tubes, and a comp 230/232 592/595 111.

The car is primarily a daily driver that sees the occasional auto cross and track event. What Im looking for is 243 heads, under $2000, and my primary concern is low end torque more than high end horse power and big dyno numbers.

Ive gone through the search function, and looked at a number of options, and right now Im leaning towards the Livernois Stg 3 243 heads milled to 61ccs but Im open to any and all suggestions.

Thanks

2QUIK4U

iTrader: (7)

I would send your heads to AI and have them ported. They do a great job and will be well within your price range.

mark21742

2quik4u has the same opinion I do....for the money you cant go wrong....you might see if they do an exchange, so there is less down time for you....that way as soon as they get your heads they can send the new ones right out

mac62989

iTrader: (1)

AI would be my vote as well. TEA, Texas speed, and Livernois sell ported/will port 243s as well. In the dyno section recently was a Z06 that made great numbers with Livernois Stage 3s I believe.

FLYNAVY30

iTrader: (1)

Yea I saw that thread about the Livernois heads. I contacted TEA about a core exchange, which they said they would usually do, but didn't have any 243's in stock at the moment. I may give AI a shout this week to see if they'll either sell a set outright, or do an exchange.

garygnu

if you could find some used air flow research heads for $2000 that would give you the power you want.look at some Texas Speed heads .you can find used 243/799 heads for $400 used ,then send them to the mentioned shops for porting .

Blk98Vert

iTrader: (2)

I have CBM 243s on miine and Im happy with them

mac62989

iTrader: (1)

I know you can buy brand new 243s from AI. In any case if you bought a set of new or used, once installed you could sell the ones off of your car and make at least $400 back. I originally missed the part that the car is a daily so Im sure you dont want any downtime..

dr_whigham

iTrader: (49)

Don't do the "exchange" with AI unless you're sure they have hollow/sodium valves, which your 2003 Z06 does have.

PREDATOR-Z

Send YOURS to AI for a 226cc program. Make sure you keep YOUR stock lightweight valves. Do not mill that much (61cc), your cam might be too close for comfort on PTV clearance.

FLYNAVY30

iTrader: (1)

Do you really think that at 61ccs the PTV clearance will be that close? I realize the only way to know for sure is to measure with the heads on the car....TEA actually suggested the milling to 61cc with the factory head gasket and my cam, they said I wouldnt have an issue.

427LS7HCI

Just mill to 62 and call it a day

FLYNAVY30

iTrader: (1)

Fair enough.....calling AI this afternoon....

PREDATOR-Z

What is the ICL of your cam (111 LSA + how much advance?)

FLYNAVY30

iTrader: (1)

No idea unfortunately....it's MTIs old V1 cam....they did the install while I was on deployment back in 2008

PREDATOR-Z

Usually, off shelf cams are +4, the V1 was Compcam XER. At 61cc, stock valve and gasket, it will be too close.
Even at 62cc, my advice is measure PTV clearance with a dial indicator and based on that make a judgment. I would not run less than .070 on the street and .090 exhaust.
If it were me, I would install heads with ARP studs unmilled. measure then decide if I could mill and by how much.

FLYNAVY30

iTrader: (1)

Ok thanks for the input....my LS rebuild manual said not to go below .080 on the intake and .100 on the exhaust on a street car so I may just keep it at the factory 64cc chambers. Again I'm more concerned about reliability than squeezing every last ounce of power out of it

gtotoocool1

iTrader: (6)

i'll go against the grain here and suggest you stick with your original 243s.if your not concerned with all out power,your stock heads should work fine..maybe have AI freshen them up a bit with a good VJ and make sure the surfaces are flat..it all depends on how much your willing to spend per HP i guess..and listen to Pred about the P/V clearance..

PREDATOR-Z

Yes .080/.100 is the average 'safe' distance but many big cam run much less. A racing motor is allowed shorter distance to fit "mega" cams. This is where attention to details pays off to limit disastrous results. Details such as p-rod deflection (racers use thicker p-rod), matching components is critical for more reliable operation. (just for curiosity look at Utube Spintron videos on valve train). Even at those margins .08/.100 (if the valve train is not correct) contact can be made on huge cams or too much milling).
I usually flycut when I mill heads to raise compression. GM should make it standard operation to have their OEM slugs with reliefs IMO)
On my setup (sig) I have .100 intake and .120 exhaust with my 2cc reliefs. That is a pure street setup.
Keep in mind that a CNC ported head will have chamber work therefore increasing chamber size (not 64.5cc) as stock. So to mill to a certain smaller cc requires more mill than on stock to achieve desired chamber size. Proper protocol requires measuring chamber with burret.

Jason 98 TA

iTrader: (4)

You might consider the PRC 227 heads. Without springs they're 2k, with springs they're 2200. That being said you'll be able to sell your 243 heads & end up with roughly 1500-1700 in the aftermarket casting heads.

The PRC 227 head is the highest flowing current production 3.9" bore cylinder head out there. Its designed as a max effort cylinder head specific for small bore applications! You can get a 59cc chamber and have very close to stock p/v clearance even with the 2.065" intake & 1.60" exhaust valve.

Just something to think about if your looking for the best possible power output