They were fairly common back in the day. I would think any local machine shop would be able to do it for you. Which one do you have? I know that they were rated by torque instead of cubic inch. I think the 445 was the bad motor scooter that they put in the Wildcats and maybe some riveiras. There was also a 410 which is probably the more common ones. Most of them say Wildcat on the motor but unless they came out of a Wildcat body or a Riv, they were not the 445. I have also been told however, that the factory used thicker head gaskets to lower the compression on the 410's and that you can use a thinner one when you have it rebuilt to get the compression of the 445. I'm sure the 445 had other mods as well, but that is all I know about. Good luck! These are good motors!
I know that your message about rebuilding a nailhead goes back awhile, but you might want to check out http://groups.yahoo.com/group/BuickNailhead there are over 300 guys using this website to swap info about nailheads. Hope this helps. Bob
if you have a healthy factory built nailhead that sounds good and runs smooth after atune up DO NOT rebuild it. itis still around for a very good reason... because it was built right. my long time experience with these dynaflow cars is you seldom find one with a bad engine. (not so with the TH-400 jobs however) i think the dynaflow made it easier on these engins is why the held up so good. seen a few 64-66 models with shift trans not so good, i think bottom end too small -probably why buick went to 430/455.