Head gasket recommendation

yellow rose said

You are right in the dowel pins only hold the gasket in certain areas. They have zero affect between the bores, where most failures occur. I'm talking about what they used to call gasket migration, where the entire gasket would move around. Every time a cylinder fires it lifts the head off the block. Every time. And the gasket has to follow this movement or it fails. That's what the dowel pis do after the head is bolted down.

If you control speed and feed, and grinding stone will produce a mirror finish. It is the multiple cutter style of surfaces that have issues. Especially if you have one or two cutters not perfectly located.

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Thank you; I learned something new on the milling processes.

I ran some rough numbers, and if the typical peak combustion pressures were static (i.e., held forever), then a typical stock SBM head bolt would be stretched a few thousands over the normal torqued-in-place length. Of course, the peak pressures only last a millisecond or less, so that makes the actual movement much less. But I never considered how much it might move the head just from combustion pressures. So thanks for bringing that up.

Here is an article that gives some info on the forces and bolt/stud elongation involved. The numbers mentioned hang with the numbers I was running.
Perfect Engine Sealing Starts With Proper Head Bolt Use - Engine Builder Magazine