I am in a similar situation with my 216, and am still working out the latest gremlins now after several years of issues. If you put on a new vacuum advance, it may be the distributor installation. Just a guess. I have also never heard of the term pressure in the head. What is that and how did they determine that is a problem? I am glad you towed it home, I hope you bid this guys a good by and make sure that they see no more of your business. Only thing I could suggest at this point, is check for distributor timing/ proper installation, vacuum leaks and do a compression check to see if everything is OK.
