Block Test Fail / Oil in Coolant

Just fixed oil leak in Oil Filter Housing. Noticed coolant looked pretty bad, don't know last time it was changed. Only drained about a gallon plus to change the oil filter housing. Refilled with 50/50 mixture, but didn't test very good on the temp gauge. I took it to pep boys to do a coolant clean and flush. They said it failed the block test and couldn't do the service. I went back and looked at the coolant and it did have a bit of oil in it. I put some stop leak in to hold me over till I can get to figuring out what to do.

Any suggestions? 93 Crown Victoria.

Compression test.