Yup, done this 2x now. Not bad, just a PIA, since removing the trans is tough to get it back in, and pulling the whole engine involves draining everything.
Just out of curiosity, how are you sure its not the HG? Did you do a compression test? If its the stock HG, they almost ALWAYS go bad until you put a MLS head gasket in it.
And yes newman, new engines do cost around 100 at a junk yard.
–mark