GTO Camshafts
The following list are some applicable GM camshafts. Please note some are Production part numbers, some Replacement or Service part numbers, and some are Performance part numbers. I will list them as such and give specs where I can. ??? at the end of a spec means uncertain. As always, trust, then doublecheck. The sources are the Clay Chevrolet (Newton, MA.) Parts Department and the 2002 Performance Parts CD, and 2003 & 2004 catalogs.
12560965 - 320HP LS1 w computer Service engine camshaft part number.
207*/196*@.050, .479/.467, 116* LSA (F & Y body)???
(Lobe lift specs in Helms component tables for GTO) (350HP?)
12561721 - 2004 GTO camshaft service replacement part number (Clay)???
200*/203*@.050, .500/.500, 116* LSA ???
(Lobe lift specs in Helms inspection procedures) (???HP)
12560950 - Current Gen III LS6 Vortec OE production cam GMPP number.
207*/217*@.050, .525/.525, 116* LSA
12565308 - 02/04 LS6 Corvette production cam GMPP number.
204*/218*@.050, .550/.550. 117.5* LSA (In Autocross Version)
12480033 - Comparable to LT4 Hot cam GMPP number
(includes 16 LS6 Valve Springs #12565117)
219*/228*@.050, .525/.525, 112* LSA
12480110 - Gen III LS1 ASA Racing cam GMPP number
226*/236*@.050, .525/.525, 110* LSA
I have unearthed a lot of Specs on the specific production LS1's we own in the GTO, but have no accompanying numbers yet, things like the tapered LS6 Valve Springs installed being 76 pounds closed and 220 open, the injectors being 28.8 pound per hour units, valve sizes, head cc's, etc. I'll post specs under the proper section when I can organize them. I'll keep this updated as specs can be verified and I can doublecheck with the Helms and correct errata.
GTO Valve Springs are possibly #12565117, 76 pounds at installed height of 1.80 inches, 220# open at 1.32 inches per the Helms, the test specs would indicate a valve lift of .480 inches...???
From GMH GTO: GOOD NEWS! GTO heads have the latest LS6 valve springs, Old Goat your source is perhaps misled or information was mixed up. Intiallly 2001 LS6 springs had a blue stripe for .525" lift superseeded by Yellow stripe on the 2002 springs and puke green color stripe on the 2003 LS6 valve springs rated for .550" lift.
