I am having a strange problem with my '70 Cutlass convertible. The coolant is foaming. I don't find any coolant in the oil. I thought maybe I had a head gasket or head problem. I took compression readings on the engine and found 3 cylinders at 145 psi, 4 cylinders at 150psi, and 1 cylinder at 158psi. I am looking for someone who can tell me what the baseline readings should be close to. The engine is a 1970 350ci olds. I don't know the compression ratio, because when I built the engine I had two engines apart at the same time, and i don't know if I got the high compression heads rebuilt or the low compression heads rebuilt.
Has anyone seen foaming coolant before? I think that i saw it once before in a 350ci Olds that I had with one dead cylinder. The cause of that may have been the previous owner mixing ceramic engine seal with the coolant before i bought it.
He left the empty can of moroso engine seal in the trunk, so I knew that engine was suspect once I started having trouble. This engine has less than 5000 miles on it since I rebuilt it.
Any suggestions and an idea on the compression readings will be greatly appreciated.

Had the foamy coolant once on an old ford. No coolant getting in the oil. Also the coolant looked fine after it cooled down. But when i cranked it the next morning and when the thermostat opened i imediatly had coolant going into the overflow tank under preasure. Thats when i knew to i had a blown gasket. I hope your problem is more simple to fix.