The 5.7 heads are LS1 and the 5.3 are truck heads, which ones do you like?
CNC 5.7 II CNC 5.3 II CNC 5.3 1.5
Lift Int Ex Int Ex Int Ex
.100" 65 53 65 55 65 55
.200" 135 102 139 110 139 115
.300" 198 146 200 155 200 172
.400" 245 194 250 208 250 227
.500" 282 223 285 240 285 257
.550" 292 233 295 250 295 265
.600" 296 240 300 255 300 270




[Modified by extremecorvette, 10:44 AM 7/10/2003]

 

Sure you have those right, the stage .15 5.3s are flowing better ont he exhaust side than the stage IIs?

 

Nate,
Don't forget about the 'Showroom Stock Racing' pieces available directly from General Motors Performance Products. These are serious performance products strait from the General. Below is the technical information and parts you'll need/want. Also, call around for pricing as nearly every dealer with have a different discount. My personal experience was that by calling nearly a dozen dealers I ended up saving around $600 which went a long way towards the LT Headers. Listed below is what I paid which is a fairly good deal in my opinion. Especially when you take into consideration there is no core charge. Yes, unlike most vendors you pay as much or more and lose your pieces. I like to keep all of my stock pieces just in case.
Good Luck, Buddy!

88958622 Head, Gen 3 Aluminum Racing
This cylinder head starts with the production LS6 cylinder head and is then CNC ported for maximum flow. It is the cylinder head of choice for Corvette showroom stock road racing. With this cylinder head and the ASA camshaft, Gen 3 engines can approach 500 horsepower in racing applications. This cylinder head includes production LS6 valve springs and valves.

$1,021.50 each

Technical Notes: These ported heads are race only. Not for street usage.

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88958606 Roller Camshaft "Gen 3" Showroom Stock Design
This hydraulic roller camshaft for RPO LS1 or LS6 was designed for showroom stock road racing. It requires the use of 2002 and later LS6 hollow stem intake valves P/N 12565311, hollow stem - sodium filled exhaust valves P/N 12565312, and valve springs P/N 125565313. It features .570" intake and exhaust lift, 251 degree exhaust duration at .050" and 239 degree intake duration at .050".

$462.88 each

Technical Notes:
• Center line of intake lobe means M.O.P. or maximum open point, determined across nose of lobe.
• Lobe flank is not symmetrical - for best torque set intake to TDC@105 degree and for best per set intake to TDC@106.5 degree.
• Cam timing @ 0.050" tappet lift (timed @106 degrees intake to TDC)
• Exhaust opens @ 51 degrees and closes @ 20 degrees with duration at 251.
• Intake opens @ 12 degrees and closes @ 47 degrees with duration at 239.

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12498545 Cylinder Head Bolt Kit "1997-2004"
This bolt kit includes fifteen head bolts for 1997 through 2004 LS1 Camaros and Corvettes and LS6 Corvettes. This kit services one head only. Two are required per engine..

$16.05 per head

Technical Notes: Head bolts cannot be reused on these engines.

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12498543 Cylinder Head Gasket Kit "1997-2001"
This gasket kit includes two head gaskets for 1997 through 2001. LS1 Camaro and Corvette, plus 1991 Corvette LS6 engines.

OR

12498544 Cylinder Head Gasket Kit "2002-2004"
This gasket kit includes two head gaskets for 2002 through 2004 LS1 Camaro and Corvette.

$33.41 each

:flag

 

The CNC heads from GM are nice. But there are much better cams than the ASA cam. The cam you are pointing him to is the 'Gib' cam, and it is a super radical cam. It makes good power but most folks don't run it on a streeet car. To work with the stock springs on the CNC heads it has slow ramps. Better cams with faster ramps and around the same power are avaliable. But beter springs are in order. Of course, you can buy a fully ported set of 5.3L heads for $1295 per pair (from patriot) that flow around what the CNC heads do, so if cost is your issue, you may wish to consider that.


[Modified by J-Rod, 3:40 PM 7/10/2003]

 

I'm just looking at heads right know and saw that these 5.3 head are flowing better on paper than the Stage 2 heads and the almost the same numbers as the LS6 heads. The 5.3 have are flowing more on the exhaust side than the stage 2's