Advanced Induction Cylinder Head Development
100% CNC'd 232cc Big Valve GM LS6/LS2 Cylinder Head Package

This is a version of our 232cc full CNC work with a larger 2.055" / 1.575" valve set instead of the stock 2.00" / 1.500" valves.  It is mainly helpful on 4" & larger bore applications running large high lift cams, and adds approximately 15-30hp potential to the head depending on build (stock short block vs. more stroke / RPM).  This can put 6L stock short blocks over 500rwhp, and strokers well over 500rwhp.  The highest #'s reported for a typical hydraulic roller street build have been over 550rwhp / 525rwtq SAE on a Dynojet.  It can be particularly helpful for 4" stroke apps.  Works best with at least 230deg of cam & .62X" net lift.  Properly running the larger valve entails cutting out the stock seat inserts, and machining the seat counterbore for a larger aftermarket seat insert to ideally fit the 2.055" intake.  The premium over the standard 232cc CNC work includes the additional machining, aftermarket intake seats, and a full set of Manley Race Series Stainless Steel valves.

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
  • Manley Race Series 2.055" Stainless Steel Intake Valves
  • Manley Race Series 1.575" Stainless Steel Exhaust Valves
  • Larger Aftermarket Intake Seat Inserts Installed
  • PCD milled to ensure flatness, surface finish, & achieve desired chamber volume (57 - 67 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
  • Pushrod Clearance Machined for larger pushrods + Geometry Improvement for High Lift Cams
  • Professionally Setup & Assembled for your individual application - Ready to bolt-on & Run
Machining & Labor Cost: $2495

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

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




Dyno, Flow Bench, and Track Results: