most of these old motors have been rebuilt at one time or another usually by a machine shop a large one. back before the 80's like sun motors in tulsa they used to redo 100 motors or more a day at one time. they did not worry about the #on the engine being the one you turned in other than the casting # & the code on the block identifying what size it was and the casting #on the head. when i had them re-do my 235 in 1977 the motor i got back was not the same one. i wrote the #'s down before i dropped it off.they had their own tag on it. just like a head re-man shop or trans re-man shop. a friend of mine does automatic transmissions and he has lots of cores lying around if one needs welding he just installs one he has already on the shelf now if you want yours back in there you better tell him up ft or he will install one already to go in 1 day that is how they do it all the time. when i ported a lot of cylinder heads on harley's you got yours back. on racing heads they always got the ones back they are of a certain design and chamber size and so on. i had core heads on the shelf all the time ready to go of different types of the porting that i offered.i also charged a core charge if you just wanted to by a set of ported heads i had done but wanted to keep your original heads or had damaged your heads to bad. a lot of people used to do it all the time.even though they say those heads are seasoned to those cylinders and so on once i milled em to clean the gasket surface or adjust compression they just bolt back on but are seasoned heads because of the heat cycles not just because they came on that motor it really makes no difference other than personal preference. on muscle cars like roadrunner's,corvette's,firebird's,camaro's,charger's etc it does make a big differernce at auction's and personal collectors type of situations.harley's now have #'s on six different parts even the lower triple clamp on the ft end of the bike. they get stolen alot.
