Advanced Induction Cylinder Head Development
Ai 260cc CNC'd GM 823 L92 Cylinder Head Package

GM's #823 rectangular port casting has decent potential out of the box.  Our 260cc Budget CNC option is a great choice for guys who would like to realize most of the potential gains available with the 823, but are not inclined to port the casting to its ultimate potential.  This additional gain is attained via fully CNC porting the exhaust runners, CNC machining the valve seat area, & blending into the bowl area of the intake port as necessary.  The remainder of the intake port is left as cast.  Combined with our high end CNC valve jobs, precision valve grinding, and milling, the head is bumped into the 600hp+ potential range.  Typical gains for this option are in the 20-35rwhp SAE range over the as cast 823.

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.


Machining & Labor Operations:
  • 100% CNC Contoured Combustion Chambers
  • 100% CNC Ported Exhaust Runners
  • 100% CNC Professional Competition Quality Valvejob
  • Factory Valves Cleaned & Precision Ground
  • PCD milled to ensure flatness, surface finish, & achieve desired chamber volume (62 - 73cc)
  • Intake Flange, Exhaust Flange, and Valve Cover Rail PCD Milled to new surface finish specs
Machining & Labor Cost: $995


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



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