I have started my first solo rebuild on a big block 396 that used to
belong to my Dad. So far the heads are refusing to come off. I don't
want to get too rough with them for fear of damaging the gasket surfaces
or cracking them.
I tried a pry bar but it seemed to hold so well I know would have
damaged it before it gave up. I have also tried using a length 2x4 for
some leverage, wedging it under one head and one top of the other which,
didn't seem to do anything.