GM's #241 5.7L LS1 head casting is one of the most commonly available GM castings out there.  While often swapped out in favor of 243's, the venerable 241 is still capable of producing great power for the $ considering how cheaply the castings can be obtained.  At only 15 cc over stock volume this particular port sees gains of over 50 cfm on the intake utilizing a factory GM 2.00" valve.  Our 241 CNC work has found success amongst enthusiasts looking for significant gains and no losses down low without sacrificing quality or longevity.  Typical gains for our CNC work are in the 40rwhp SAE range over the as cast 241, and many 346cid LS1's manage 420-460rwhp SAE with 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.  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 (60 - 72 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
• Deburring of Entire Casting + fine detail softening of all edges in & around combustion chambers
• Professionally Setup & Assembled for your individual application - Ready to bolt-on & Run

Machining & Labor Cost: $1795

Please Contact Us for shipping & turnaround quotes.


Labor and Component Options:

Note: GM LS1/2/3/6 guides 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 (heat, etc.), we have several options.  GM OEM valves are generally high quality, durable, and lightweight.  Most naturally aspirated hydraulic roller applications do not necessarily need an aftermarket valve.  In many cases, common entry-level aftermarket valves are a significant downgrade.  If you have "extra" $ to spend, upgrade springs & components first, and invest in our high quality valve options for durability, performance, and safety margin second.  If budget allows, doing both is worth the $, particularly in the long-term.

Suggested Setups -

• Long-Term Mild Street Toy to DD:  PSI 1511's, ~.600" net lift or under.  Retain OE guide & valve set if in good condition.
  
• Typical Street Hot Rod:  BTR Duals, or upgrade to PSI's or PSI's w/ our Lwt Retainers if budget allows.  Typically ~.6XX" net lift.
  
• Aggressive Hyd Roller:  PSI UHR Spring Kit, Possibly one of our PSI Pro Kits depending on application.  ~.6XX-.7XX" net lift.
  
• Solid Roller:  Long-term mild, aggressive street, to full race engineered valve-train systems, etc. - P.O.R., Quoted Per Application
  
• Camshafts:  Have something made for your specific setup & goals.  Guaranteed compatibility.  100% QC Inspection.
  
  Other setups are available for racier applications, compliance with class rules, etc. (e.g. PSI duals & our professional racing grade components, Xceldyne components, Jesel rocker systems, etc.).  All of these will be set up ideally to ensure you maximize the potential that any given components offer.

Bronze Guide Liners installed & honed to ideal clearances to refurbish worn out guides. - Cost: $250
Replace OEM guides with Ai Pro Racing Quality Full Bronze Guides & hone to ideal clearances - Cost: $295
Replace OEM guides with Ai Pro Racing Quality Custom Guides - Material & Dimensions per application - Cost: Quoted Per App

Ai PSI 1511 MaxLife Endurance Springs w/ Hardened Steel Locators & Viton Seals. 100% QC - Cost: $385
Ai PSI 1516 High Lift MaxLife Endurance Springs w/ Hardened Steel Locators & Viton Seals. 100% QC - Cost: $410
Ai Ultimate HR Kit w/ PSI MaxLife High Lift springs + Ai Lwt Tool Steel Retainers, Machined Locks, Locators, 100% QC - Cost: $600
Ai Pro-Series PSI Dual Spring Kit w/ Professional Racing Quality Components, .6XX" Lift w/ Stock Rockers. 100% QC - Cost: $995
Ai Pro-Series PSI Dual Spring Kit w/ Professional Racing Quality Components, .6XX"-.7XX" Lift HR or SR. 100% QC - Cost: $1195

Ai Lightweight Tool Steel Retainers for beehive style springs. Lighter than Ti Dual Spring Retainers - Cost: $195
Manley Titanium Retainers for OEM, PAC, PSI, etc. beehive style springs - Cost: $235
BTR .660" Polished Dual Spring Kit w/ locators, viton seals, & Titanium Retainers - Cost: $310
Manley Nextek .660" rated shot peened & polished Dual Spring Kit w/ Titanium Retainers - Cost: $435
Manley Nextek .700" rated shot peened & polished Dual Spring Kit w/ Titanium Retainers - Cost: $735
Manley Nextek .800" rated shot peened & polished Dual Spring Kit w/ Titanium Retainers - Cost: $860

Manley 'Race' Series, Good Quality Stainless Replacement Valve Set + Ai Prep - Cost: $350
Ferrea 6000 Series, Better Quality Stainless Replacement Valve Set + Ai Prep - Cost: $450
Ai Custom Designed Max Effort Hollow Stemmed Stainless Intake & Exhaust Valves for NA applications - Cost: Quoted Per App
Ai Custom Designed Max Effort Hollow Stemmed Intake & Inconel Exhaust Valves for high EGT applications - Cost: Quoted Per App
Ai Custom Designed Titanium Intake + Coatings & Ai Custom Hollow Steel OR Ai Custom Inconel Exhaust Valves - Cost: Quoted Per App