A question about cylinder heads - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

St33lsinger · 02-10-2010, 09:27 AM

I am getting the SS with the Automatic transmittion. I know this is the L99 enigne. So here is the question. What heads are on this engine?
L92?? (if thats a head number) or what.

And since I am thinking about porting and polishing or just replacing them with some high flow heads...I need a good place to get them.

Thanks

Robin Lawrence · 02-10-2010, 09:36 AM

Those heads would be the same as the LS3. The L92 and the L76 as well as the LS3 share the same castings. The difference would be in the intake valve and the valve springs.

The LS3 and I believe the L99 share a hollow stem intake valve. The LS3 uses the yellow spring good to .570" of lift. I think that the L99 uses the same spring.

Robin

St33lsinger · 02-10-2010, 10:23 AM

thanks man

barrylnv · 02-10-2010, 08:04 PM

I'm not sure if the L99 has hallow valve stems (sodium backfilled) like the LS3. I know the redline is less than the LS3 (6200 vs. 6600) but not sure if that has more to do with VVT or cam profile or lack of hallow stems. I have read the LS3 and L99 use the exact same casting and that casting is similar to but not identical to that used on the L92. I think the exhaust port openings are bigger on LS3/L99 applications. Before spending a bunch on aftermarket heads I'd recommend talking to a good tuner or builder about porting the heads. They already have great flow numbers.

wbt · 02-10-2010, 09:49 PM

CNC porting of the stock heads will do you just fine.

St33lsinger · 02-24-2010, 09:19 AM

I think thats what I am going to do. I understand the HP gain is upwords to 120 HP.

Does that sound right?
I know I did my 78 Z28 and gained close to 150 hp, but that had bigger valves too.

SRT10KLLR · 02-24-2010, 09:26 AM

Quote:

Originally Posted by Steelsinger

I think thats what I am going to do. I understand the HP gain is upwords to 120 HP.

Does that sound right?
I know I did my 78 Z28 and gained close to 150 hp, but that had bigger valves too.

No way you will ever get 120 hp more from ported and polished heads. More like 25 hp on a set of average heads and 45 hp on the high end with some good 3K heads.

Texas Speed had some very reasonable heads for like 1K that give you 20-25 hp and Mast Motorsports has some 12 degree heads for $3,000 that came 45+.

Jason 98 TA · 02-24-2010, 10:29 AM

We are working on a aftermarket casting LS3 head, but it's a long way away right now. :( Currently we're cnc porting customers factory heads for right around $800.

Qwkss · 02-24-2010, 10:32 AM

Quote:

Originally Posted by Jason 98 TA

We are working on a aftermarket casting LS3 head, but it's a long way away right now. :( Currently we're cnc porting customers factory heads for right around $800.

Flow numbers before and after?

Darin Morgan · 02-26-2010, 10:40 PM

Quote:

Originally Posted by Steelsinger

I am getting the SS with the Automatic transmittion. I know this is the L99 enigne. So here is the question. What heads are on this engine?
L92?? (if thats a head number) or what.

And since I am thinking about porting and polishing or just replacing them with some high flow heads...I need a good place to get them.

Thanks

You should find most if not all the info you want about the heads on my Journal. I just posted spec, flow figures and power gains from porting yesterday and today.

http://www.camaro5.com/forums/showth...t=42255&page=2

St33lsinger · 03-01-2010, 09:32 AM

Quote:

Originally Posted by Jason 98 TA

We are working on a aftermarket casting LS3 head, but it's a long way away right now. :( Currently we're cnc porting customers factory heads for right around $800.

What kind of numbers are we talking about for a L99?

I guess I am trying to figure out if it is worth the extra cost. As it is right now this is what I am going to have done.
• Kooks Headers 1 7/8" tube
• Kooks High Flow Catalytic Converters
• Kooks Mufflers
• 3 inch High-Flow Stainless Steel Mid-Pipes
• Corsa Dual Rear Exit Exhaust System
• VARARAM or New Era CAI
• port and polish heads
• NKG Spark Plugs
• Retune

I am looking to pick up at least 70 HP.
Does that sound right?

St33lsinger · 03-03-2010, 12:38 PM

See above

Steve@Vectormotorsports · 03-03-2010, 01:50 PM

Quote:

Originally Posted by Steelsinger

What kind of numbers are we talking about for a L99?

I guess I am trying to figure out if it is worth the extra cost. As it is right now this is what I am going to have done.
• Kooks Headers 1 7/8" tube
• Kooks High Flow Catalytic Converters
• Kooks Mufflers
• 3 inch High-Flow Stainless Steel Mid-Pipes
• Corsa Dual Rear Exit Exhaust System
• VARARAM or New Era CAI
• port and polish heads
• NKG Spark Plugs
• Retune

I am looking to pick up at least 70 HP.
Does that sound right?

No camshaft? without a cam, porting your factory heads will gain very little if any. You'll find the camshaft will be your limitation. Our stage 2 cam with supporting mods gains over 100hp on an LS3 over stock with stock heads untouched.

Lonnie@Texas-Speed · 03-03-2010, 04:13 PM

Quote:

Originally Posted by Qwkss

Flow numbers before and after?

It's actually $750 to port and valve-job the LS3/L99 heads. Here's a link with some more info and flow data on the PRC heads including spring and valve options with pricing!

Let us know if we can help!

http://www.texas-speed.com/shop/item...=1066&catid=20

02-10-2010, 09:27 AM	#1
St33lsinger Emerald Coast Camaros Drives: 2010 1 RS/SS Join Date: Jun 2009 Location: Florida Posts: 1,095 View My Garage	A question about cylinder heads I am getting the SS with the Automatic transmittion. I know this is the L99 enigne. So here is the question. What heads are on this engine? L92?? (if thats a head number) or what. And since I am thinking about porting and polishing or just replacing them with some high flow heads...I need a good place to get them. Thanks __________________ Had: 69' RS, 78' Z28, 98' SS Have: 2010 1RS/SS

02-10-2010, 09:36 AM	#2
Robin Lawrence Drives: 2010 Camaro 69 Nova Join Date: Oct 2008 Location: Galesburg, Illinois Posts: 447	Those heads would be the same as the LS3. The L92 and the L76 as well as the LS3 share the same castings. The difference would be in the intake valve and the valve springs. The LS3 and I believe the L99 share a hollow stem intake valve. The LS3 uses the yellow spring good to .570" of lift. I think that the L99 uses the same spring. Robin __________________ Holley Performance Products

02-10-2010, 10:23 AM	#3
St33lsinger Emerald Coast Camaros Drives: 2010 1 RS/SS Join Date: Jun 2009 Location: Florida Posts: 1,095 View My Garage	thanks man __________________ Had: 69' RS, 78' Z28, 98' SS Have: 2010 1RS/SS

02-10-2010, 08:04 PM	#4
barrylnv Drives: 2010 2SS IMB LS3/M6 Join Date: Jul 2009 Location: Reno, NV Posts: 137	I'm not sure if the L99 has hallow valve stems (sodium backfilled) like the LS3. I know the redline is less than the LS3 (6200 vs. 6600) but not sure if that has more to do with VVT or cam profile or lack of hallow stems. I have read the LS3 and L99 use the exact same casting and that casting is similar to but not identical to that used on the L92. I think the exhaust port openings are bigger on LS3/L99 applications. Before spending a bunch on aftermarket heads I'd recommend talking to a good tuner or builder about porting the heads. They already have great flow numbers. __________________ 2010 2SS LS3/M6 Imperial Blue 650HP LPE Package - 576.3 RWHP, 91-tune 4.10 Richmond Gears ZR1 Clutch / LPE Flywheel LPE IBM Coil Covers Thorley Shorty Headers Borla 140280 Cat-back ADM Boost Gauge MTI Shifter Hotchkis Sway Bars LPE Floor Mats SRP Heel-Toe Pedals

02-24-2010, 09:19 AM	#6
St33lsinger Emerald Coast Camaros Drives: 2010 1 RS/SS Join Date: Jun 2009 Location: Florida Posts: 1,095 View My Garage	I think thats what I am going to do. I understand the HP gain is upwords to 120 HP. Does that sound right? I know I did my 78 Z28 and gained close to 150 hp, but that had bigger valves too. __________________ Had: 69' RS, 78' Z28, 98' SS Have: 2010 1RS/SS

02-10-2010, 09:49 PM	#5
wbt Account Suspended Drives: 2010 Challenger R/T;2011 Mustang GT Join Date: Jan 2010 Location: Texas Posts: 2,105	CNC porting of the stock heads will do you just fine.

02-24-2010, 10:29 AM	#8
Jason 98 TA Drives: Camaro Join Date: Apr 2009 Location: Texas Posts: 1,669	We are working on a aftermarket casting LS3 head, but it's a long way away right now. :( Currently we're cnc porting customers factory heads for right around $800.

03-03-2010, 12:38 PM	#12
St33lsinger Emerald Coast Camaros Drives: 2010 1 RS/SS Join Date: Jun 2009 Location: Florida Posts: 1,095 View My Garage	See above __________________ Had: 69' RS, 78' Z28, 98' SS Have: 2010 1RS/SS

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