New head gaskets for more power?
Banned
Joined: Jan 2019
Posts: 1,747
Likes: 100
They say nothing of gasket thickness on the site. Don't want 2 talk to Corey nor c. straub .. May just text / FB pm GG about a Cosmetic. again GG did this yrs ago....if you knew u knew.
https://www.corvetteforum.com/forums...-question.html
https://www.corvetteforum.com/forums...-question.html
I get the wide open throttle part there is so much water flow it is going everywhere. However, at idle and low speeds by drilling holes (and looks like good size ones (like 3/8 of an inch) does it prevent the cooler water from getting into the back cylinders because water takes the path of least resistance and will go through the new gasket holes you drilled in front of the motor at idle. The 4 lower factory steam holes are like 3/16 or less so not much can go through there. Maybe a street version would be smaller holes so you get the benefits but also keep the low speed cooling in check. As a reference point the water pump hole is a 1 inch circle and the holes in the very back of the block/gasket are about the same.
Going to bump this thread as there is currently a thread going on YB about this and Straub brought it up again. Would love to see some back to backs on this...
From Straub himself
"To meet EPA fuel economy and emissions GM came up with the idea of blocking the water flow around the combustion chamber. This keeps heat in the chamber and gives better fuel economy and burns off excess gas. This is the reason for the off gassing plumbing on LS and LT heads. Note your heads have water jacket holes and your block does but your head gasket doesn't.
I was made aware of this by the supplier of an LS Crate engine. They almost melted a head on an endurance test in 2012. The simple fix of a head gasket with proper size holes decreased temp by 20 degrees, increase rpm by 700 and made 18 more HP in a an NA engine.
With his blessing I purchased a die and we have LS and LT gaskets punched with 7 extra holes. This has been since 2018 and everyone has been raved about them. We have them in 4.030 bore and 4.100 bore and can punch anyones large bore gasket if needed.
People complain and blame the seats GM uses for fallout of the heads.....Well this is the reason they do...no cooling."
From Straub himself
"To meet EPA fuel economy and emissions GM came up with the idea of blocking the water flow around the combustion chamber. This keeps heat in the chamber and gives better fuel economy and burns off excess gas. This is the reason for the off gassing plumbing on LS and LT heads. Note your heads have water jacket holes and your block does but your head gasket doesn't.
I was made aware of this by the supplier of an LS Crate engine. They almost melted a head on an endurance test in 2012. The simple fix of a head gasket with proper size holes decreased temp by 20 degrees, increase rpm by 700 and made 18 more HP in a an NA engine.
With his blessing I purchased a die and we have LS and LT gaskets punched with 7 extra holes. This has been since 2018 and everyone has been raved about them. We have them in 4.030 bore and 4.100 bore and can punch anyones large bore gasket if needed.
People complain and blame the seats GM uses for fallout of the heads.....Well this is the reason they do...no cooling."
It’s a twofold issue. One one hand, higher water temps always produce lower emissions, because of higher combustion temps. I’ve said this for years on here, that if you build two identical engines…one of aluminum and one of iron, the iron engine will always make more power because of heat in the chamber. It’s no secret that GM and most other OEM’s slowdown water flow with restrictions in the headgaskets. Since higher emissions are emitted at idle and low rpm, this approach makes sense. As the engine speeds up, the water pump pushes more water through the gaskets and cooling is increased. It’s a mechanical approach that works.
On the other hand, the restriction does cost power because of the water pump robbing power, having to force water through the restrictions. Cometic will work with you with larger cooling holes to combat this, if you contact them. Gaskets intended for race use can incorporate custom holes without emission related drawbacks that legalities can disrupt…if you guys can follow me here.
Obviously if you have the tooling to punch headgaskets yourself, that’s the avenue to go to here.
On the other hand, the restriction does cost power because of the water pump robbing power, having to force water through the restrictions. Cometic will work with you with larger cooling holes to combat this, if you contact them. Gaskets intended for race use can incorporate custom holes without emission related drawbacks that legalities can disrupt…if you guys can follow me here.
Obviously if you have the tooling to punch headgaskets yourself, that’s the avenue to go to here.
Staging Lane
Joined: Oct 2025
Posts: 89
Likes: 32
I’m going to do this when I take the head off for LS3 intake valves. You can see the 7 triangles that aren’t drilled. I won’t do holes as big as the Straub uses. Not a race car. Also adding the crossover for the rear of the head and plumbing forward to meet the front one. Already use water wetter in the coolant. Add a 180 deg stat and heat induced knock should be eliminated or greatly reduced. The gasket is also only .040” so a little bump in the compression.
