Bill, it isn't what you want to hear, but if the lifters are rusted to the block, imagine the pistons, cam, rocker assembly, valves, etc. Even if you have the very best of luck and you get it running, it wont run very well for very long. Plan on a full teardown and rebuild. Its a few grand to get the machine work done, but you wouldn't hesitate to spend that on your newer driver, and it's well worth the peace of mind. Jerry knows.
The problem with the 54, the valve cover has slots in it that allow air, dirt, water, etc to enter the engine. If it wasn't properly covered, it needs a full rebuild. Do IT and yourself a favor and just tear the whole thing down. Don't force anything and treat it very delicately. Once you have done it right, you won't be able to wipe the smile off your face! Find a good engine machine shop, check out this article so it helps you understand what you are up against..
http://devestechnet.com/Home/Project1959235It isn't as daunting as it looks. Holler if you have questions, We are here to help.
