So yesterday I pulled out my sportsman II heads that have been stashed away for 8 yrs. They were on my 406 circle track engine and I'm hoping to get them ready to go on the 406 I'm building for the Monte. So I had one on the bench looking it over and notice NO steam holes and I'm thinking WTF cuz all you ever hear is make sure you have steam holes in a 400. I ran It for 3 yrs and never had any issues with it getting hot so I don't understand what the deal is. Now I'm planning to put them on this street engine and confused if I need the holes or not?? Can't ask the builder cuz he passed a couple yrs ago. Anyone seen this before or have any knowledge about this?
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I have heard of people running them without drilling the steam holes and not having issues, I for one have always drilled my 400 heads for steam holes since you know the blocks have the holes and as far as I know most if not all the head gaskets for the 400 have them.
It is possible to have high cylinder temps or detonation but not have it read hot on your temperature gauge
It is possible to have high cylinder temps or detonation but not have it read hot on your temperature gauge
I'd get the holes drilled. Simple procedure and good insurance. Gaskets for the 400 have the holes there anyway.
My car had a 400 in it when I bought it. It wanted to run hot, especially idling. I pulled the heads and the steam holes were not drilled. I read up on the issue and planned to have the steam holes drilled but I ended up selling the engine. It needed an overhaul and I wasn't happy with the parts combination anyway, so I just went with a new crate engine.
From what I read, the steam holes are especially helpful for low speed/idling. They are not needed at high flow, high rpm so they wouldn't be needed for circle track but would be needed for the street. I looked at the installation instructions for Edelbrock Performer heads, and they said to have the steam holes drilled if the heads were being installed on a 400. I figured if GM's engineers and Edelbrock's engineers thought they needed to be there, then they did.
From what I read, the steam holes are especially helpful for low speed/idling. They are not needed at high flow, high rpm so they wouldn't be needed for circle track but would be needed for the street. I looked at the installation instructions for Edelbrock Performer heads, and they said to have the steam holes drilled if the heads were being installed on a 400. I figured if GM's engineers and Edelbrock's engineers thought they needed to be there, then they did.
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The 2025 Calendars are HERE. Two different editions, two different sizes, and a digital package!! Starting at $12.97US
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