Undercover Porting

Hidden Horsepower: “Undercover Porting” to Cast Iron & Aluminum Cylinder Heads

Looking for additional horsepower and a stock looking port?

“Undercover Porting” will get you there. At 6000 rpm, “Undercover Porting” produced 27 additional horsepower.

TEST ENGINE: 355, flat top pistons, flat tappet cam, headers 10.5 to 1 compression ratio and 500 Holley 2 barrel carb. NOTE: The intake manifolds and heads were the only components changed.


While retaining a stock looking port, “Undercover Porting” will add 15 to 30 horsepower to your engine combination. We achieve this remarkable improvement by researching each particular head to learn which areas need to be modified to gain the most air flow yet keep the ports looking stock. Since all the porting work is “covered up” and a wide bottom angle is maintained below the valve seat, “Undercover Porting” is very difficult to detect, even if the heads are pulled off. The intake port volume is increased just a few cc’s.

Undercover Porting” includes:

  • Intake ports modified
  • Exhaust ports modified
  • Chambers modified
  • Modifications are “covered up”
  • Heads are pressure tested
  • A flow bench developed valve job is performed to heads on a Serdi or Rotter machine

NOTE: The valve job is not “rolled” into the port.  A very distinct sharp edge remains under the valve seat. Yes, we can work on your bare or complete cylinder heads.

Free Custom Camshaft:

Cylinder Head Design Form:

Cylinder Head FAQs

Sending your cylinder heads to us for modifications? Check out our head shipping tips.