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Why is this head gasket not a simple circle? What’s the purpose of the design? How do you measure it if you are trying to figure out what compression ratio you had?
A little off topic topic but, is it too much work to try and figure out what Comp Cam I put in thirty years ago, or just bring it to the machine shop. I’m not planning on reusing the cam. I would like to know what my compression ratio was before a rebuild. I CC’ed the heads and piston tops. I measured the bore and stroke. Is there anything else before I pull the rest apart?
Those are valve reliefs
It is for an engine with bigger valves
Your cylinder walls would also be chamfered if it was needed for the valve reliefs
So that is possibly a boss 351 gasket for 4bbl heads that have bigger valves
My boss 302 head gaskets look the same (not round) and have the valve reliefs
The head gasket will still work (seal)
You'll lose a little compression and might have a hotspot
Those are valve reliefs
It is for an engine with bigger valves
Your cylinder walls would also be chamfered if it was needed for the valve reliefs
So that is possibly a boss 351 gasket for 4bbl heads that have bigger valves
My boss 302 head gaskets look the same (not round) and have the valve reliefs
The head gasket will still work (seal)
You'll lose a little compression and might have a hotspot
Thanks. That makes sense. I’ll have to make sure I don’t make that mistake again.
iIt’s probably a waste of time for me to figure out what compression I had before, since I’ll be rebuilding it. But I would like to know what I had before so I know what to expect excitement wise when I get to run it again. Maybe I’ll try and CC it with the kit I just bought, instead of using the thickness and diameter?
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