GM's 5.3L LS1 head casting serves as the basis for this high compression / naturally aspirated oriented 3.900" bore specific offering. With your 5.3's, lightweight Manley Race Master Stainless valves, and lots of available P2V this is a great option for 440-480rwhp 3.900" bore builds. Our GM 5.3L CNC work will generate 11:1 compression on a stock 346cid LS1 while retaining the stock available P2V which allows the use of large duration cams without cutting piston reliefs! Static compression ratios into the 12.X:1 range are possible. Typical gains for this CNC work are in the
40-50rwhp SAE range over the as cast 241, and 346cid LS1's can manage 440-470rwhp SAE
with full bolt-ons and one of our daily drivable HR cam grinds. Pricing
is for work applied to a pair (2) of cylinder head castings and components YOU supply
unless otherwise noted.
Note: Over the years we have found these castings tend to require more time in regard to quality checks/corrections on our end. They also must be run with a larger aftermarket intake valve. Due to this, the cost is higher when using them as a base for work compared to the more common GM 243 etc.
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 (50 - 60 cc)
- 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 + Manley Race Master 2.00 Intake Valves (using your stock Exh valves) Cost: $1395
Machining & Labor + Manley Race Master 2.00/1.55" Valves Cost: $1495
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