a couple things. "sprayed" probably means with some kind of light oil to keep from rusting. do you know if the heads were shaved at all? if they had enough taken off of them you're going to want to have some taken off the intake to match. i would have a machine shop go over the heads. make sure the valves don't leak, check the valve springs (unless you're going to get a "cam kit" w/ lifters and springs, i would. you will need to mock up the motor and see if there's any mis-match at the port faces. you should be able to re-use the rockers and shafts, but inspect for wear and post some pics to get a second opinion. pushrods are going to depend on what you find during mock up.
a lot of others here can help with checking push rod length
