I'm wondering if the .028 gaskets or other similar thin gasket available. Also, I'm wondering how I might check these #7 heads I bought to see if they have been milled. Are there dimensions I can measure?

 

Check out Cometic MLS Head Gaskets they are available in various thickness including .027
https://www.summitracing.com/parts/c...ake/oldsmobile
They are pricey at $94 each.

I don't know a dimension you can use to check if they have been milled. CC'ing the combustion chambers will give you one of the numbers to calculate the compression ratio.
If you have excel download a compression ratio calculator like the one found on this page: https://www.us.mahle.com/en/motorspo...h-information/

 

Measure the combustion chamber volume. This will give you exact data that can be used to calculate the compression ratio to determine the appropriate piston dish and head gasket to use.

 

Unfortunately the cheaper .028" are no longer available. As said, measure the chamber. A piece of plexiglass, vaseline and a syringe. I used coloured washer fluid, easier to see.

 

Post a picture of the deck surface of the heads. I should be able to tell you if they have been milled.

 

I was thinking, what if it's obvious that either 1) the heads have been milled, or 2) the heads have not been milled.

What does this do for you? Either way you don't know the combustion chamber volume since the volumes varied due to manufacturing tolerances, so the next step would be to cc the chambers to determine the volume.

 

Correct !!!!

 

I remember Smitty used to offer .011" ones but can't get a hold of him on Facebook. Did he sell his inventory or drawings to someone?