170 Dart compression advise???? please??

I just finished doing the oil in the cylinders trick, the pressure in every bad cylinder came up at least 20psi.
I was told that a bad head gasket might lower compression, but after doing the oil trick it looks like rings I guess.
Does anyone know if the oil in the cylinders could have helped the compression if it is a bad head gasket??? Or is there a way to test for a bad head gasket?? Sorry for the rookie questions, but I am hoping this is something that I can fix. I don't think that I'm ready to get into the block, and I'll miss that old 170. Thanks again for all your help!