Chevy Open Chamber Cylinder Heads

Chevy Open Chamber Cylinder Heads

15 to 20 more horsepower with “Undercover Ported” Open Chamber heads

We have been working with the Chevy “Open Chamber” heads for years. If your rules require the use of “open chamber” heads, the ‘441, ‘487 & ‘993 heads work the best. While these heads are not available new from Chevrolet, we have a good supply. We can also modify your open chamber heads.

Our “Undercover Porting” will improve the air flow of stock open chamber heads from 203 cfm intake and 142 cfm exhaust to 225 / 230 cfm intake and 160 cfm exhaust. This air flow improvement will result in a 15 to 25 horsepower improvement while maintaining a stock looking ports!




Below is the pricing when we have any Open Chamber head cores available.  As of 5/1/2023 we do not have cores; we will need to modify heads that you supply.  

 A BARE set of Chevy Open Chamber heads – 441, 487 or 993 – with “CNC-UnderCover Porting” which includes our CNC-UnderCover Machining, modifications to the intake ports, exhaust ports, chamber modifications, all the cover-up work, installing and sizing new bronze valve guide liners, machining the valve seats for your size valves and providing air flow numbers for your camshaft selection. Heads are also machined for screw in studs and pushrod holes opened. Cost is $1,495.00 plus shipping.

A COMPLETE set of “CNC-UnderCover Ported” Chevy Open Chamber heads – ‘441, 487 or 993 – with the above listed “CNC-UnderCover Porting” modifications, machined for screw-in studs, 11/32″ stainless valves, springs for a flat tapped or hydraulic cam, spring locators, steel retainers, machined valve locks, surfaced with a flat cut for your compression rule and assembled ready to bolt on the motor. Cost is $2,795.00 plus shipping.


We also perform operations like our “CNC-UnderCover Porting” to your bare or complete heads.

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