STAGE 1:

• Mild port and polish
• Smoothing out casting blemishes, port and gasket matching, mild bowl work, de-shrouding of the valves
• CC-matched combustion chambers
• Competition valve job (3-angle)
• LS6 valve springs, retainers, and keepers
• New Viton valve seals
• Assembled and toleranced
• Clearanced for safe lifts up to .500"

STAGE 2: - Full port and polish, port-matching the intake runners, D-shaping/re-angling of exhaust ports, significant bowl work, correcting the short side radius, polished cc-matched combustion chambers

• Race Valve Job (9-angle Intake, radiused Exhaust)
• CC-matched combustion chambers
• stainless steel swirl-polished under-cut valves in OEM diameter
• Comp Cams valve springs (128lbs at install height), Comp Cams retainers, and Comp Cams keepers
• bronze valve guide liners
• new Viton valve seals
• assembled and toleranced
• clearanced for safe lifts up to .560"
• milling up to .020 free of charge

STAGE 3:

If you're looking to build a beast of a 3X00, these are the heads that will make it happen. These are quite simply the best heads available, bar none. No expense is spared with these heads. Max intake flow is over 290cfm! The valve diameter is increased so much that if they were any bigger, they would hit.

Stage 3 - Full port and polish, port-matching the intake runners, D-shaping/re-angling of exhaust ports, significant bowl work, correcting the short side radius, polished cc-matched combustion chambers

• Race Valve Job (9-angle Intake, radiused Exhaust)
• CC-matched combustion chambers
• stainless steel swirl-polished under-cut valves in oversized diameter (*see below)
• Comp Cams valve springs (160lbs at install height), Comp Cams titanium retainers, and Comp Cams keepers
• bronze valve guide liners
• new Viton valve seals
• assembled and toleranced
• clearanced for safe lifts up to .610"
• milling up to .020 free of charge

*Heads are available in Stage 3 NA and Stage 3 Turbo. The difference between them is the valve sizes. Because the valves are as big as they can be, this option is to decide which valve should be emphasized. Stage 3 NA heads feature a 1.84" Intake Valve and a 1.52" Exhaust Valve. Stage 3 Turbo heads feature a 1.80" Intake Valve and a 1.56" exhaust valve. The bigger exhaust valve helps decrease spool time for the turbo. Stock valves sizes are 1.76" and 1.46" respectively.
For the install, you will need certain gaskets and parts. You may also purchase a gasket set from us, Genuine GM Parts at competitive rates.
The Heads Install Kit includes: an upper intake gasket, lower intake gasket, 2 valve cover gaskets, 2 headgaskets, 16 head bolts, and 2 exhaust manifold gaskets.

Because they are built to order to customer's specifications, all MMS Ported Cylinder Heads are considered a custom order and are non-refundable.  You can find further information on this and all our other policies on our Policy page here ... https://www.milzymotorsports.com/policies/