Advanced Induction Cylinder Head Development
Ai 260cc CNC'd GM 821 LS3 Cylinder Head Package

GM's #821 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 821, but are not inclined to port the casting to its ultimate potential.  This additional gain is attained via fully CNC porting the exhaust runners, and CNC machining the valve seat & bowl area of the intake port.  The remainder of the intake port, and the combustion chamber are 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 821.

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 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 - 73 cc)
  • Intake Flange, Exhaust Flange, and Valve Cover Rail PCD Milled to new surface finish specs
Machining & Labor Cost: $995

Labor and Component Options:

No CNC Chamber Contouring - Subtract: $95
Bronze Guide Liners installed & honed to ideal clearances to refurbish worn out guides. - Cost: $125
Replace OEM guides with Full Bronze Guides & hone to ideal clearances - Cost: $250

PSI 1511 MaxLife Endurance Spring Kit w/ OEM Replacement Seals. - Cost: $250
Manley 23622 Titanium Retainers for OEM, PAC, PSI, etc. beehive springs - Cost: $195
Lunati Gold dual valve spring kit w/ lightweight steel retainers.  Lift capacity to .660" - Cost: $225
BTR .660" Polished Dual Spring Kit w/ locators, viton seals, & Titanium Retainers - Cost: $300

Manley 221436 Nextek .660" shot peened & fully polished Dual Spring Kit:
    221436-16 Dual Springs
    23623-16 Titanium Retainers
    42334-16 Hardened Spring Locators
    13098-16 Precision Machined Locks
    Steel jacketed Viton seals for dual springs

    Cost: $525 bought w/ head work (This is a premium setup that is ~$700 shipped from Summit)

Please Contact Us for shipping & turnaround quotes!