GM's #243 or #799 LS6/LS2 head casting is the most sought after
GM cathedral port casting. This CNC option was designed and
produced several years ago specifically
for Grand-Am Daytona Prototype competition where 230 cc is the
maximum port volume allowed. As our current race pieces
are revised, we release these designs to the public. At a
mere 15 cc over stock volume this particular port sees gains of
over 40 cfm on the intake utilizing a factory GM 2.00" valve.
This package has found great success amongst enthusiasts seeking
area under the curve, phenomenal throttle response, and no loss
in drivability. It has also shown excellent potential in
drag applications. Typical gains are 40-50rwhp over the as cast 243, with most LS1 & LS2's producing 450-500rwhp SAE with daily drivable cams. Rick Leininger's 5.7L GTO took the NA
stock short block record after swapping to our 226 cc LS2, and the current fastest NA AWD TBSS runs this exact head.
From stock short block 346cid LS1's to 4XXcid strokers, this is a phenomenally versatile head. Pricing is for work applied to a pair (2) of cylinder head castings and components YOU supply unless otherwise noted. We are happy to build your heads with whichever spring kit, valve, etc. you would like. Please keep in mind if components you provide require additional time on our part, we must bill for that.
Machining & Labor Operations:
- 100% CNC Ported Intake, Exhaust, & Combustion Chambers
- 100% CNC Professional Competition Quality Valvejob
- Valves Cleaned & Precision Ground (whether using new aftermarket or re-using OE GM
- PCD milled to ensure flatness, surface finish, & achieve desired
chamber volume (57 - 69 cc)
- Customer can specify milling to an Available P2V Clearance relative to stock (e.g. .018" less P2V)
- Intake Flange, Exhaust Flange, and Valve Cover Rail PCD
Milled to new surface finish specs
- Thorough Inspection of Castings, Components, Bind Heights for your individual set of springs, etc.
- Complete Cleaning/Prep including Bead Blasting + UltraSonic to ensure internal passages are clear & free of debris
- Professionally Setup & Assembled for your individual application - Ready to bolt-on & Run
Machining & Labor Cost: $1195
Labor and Component Options:
Note: GM heads often show so little guide wear that they do not need to be replaced. In the event they do require attention due to wear or your application, we have several options.
Bronze Guide Liners installed & honed to ideal clearances to refurbish worn out guides. - Cost: $150
Replace OEM guides with Ai Pro Racing Quality Full Bronze Guides & hone to ideal clearances - Cost: $250
Replace OEM guides with new Powdered Metal Guides & hone to ideal clearances - Cost: $250
PSI 1511 MaxLife Endurance Spring
Kit w/ OEM Replacement Seals. - Cost: $280
PSI 1516 High Lift MaxLife Endurance Spring Kit w/ OEM Replacement Seals. - Cost: $380
Manley 23622 Titanium Retainers for OEM, PAC, PSI, etc. beehive style springs - Cost: $195
BTR .660" Polished Dual Spring Kit w/ locators, viton seals, & Steel Retainers - Cost: $230
BTR .660" Polished Dual Spring Kit w/ locators, viton seals, & Titanium Retainers - Cost: $300
Manley Nextek .660" rated shot peened & polished Dual Spring Kit w/ Titanium Retainers - Cost: $500
Manley Nextek .700" rated shot peened & polished Dual Spring Kit w/ Titanium Retainers - Cost: $635
Manley Nextek .800" rated shot peened & polished Dual Spring Kit w/ Titanium Retainers - Cost: $700