I'm parting out a '57 Chev Viking 60 truck. I have a pair of door with all working parts intact and functional; doors only lack glass. SM 420 4spd. 327 SBC that I am told may have a steel crank. Iscraped the crud off the back of the engine and the serial # is 3789817. I don't know where to check to find out what that engine has in it, but I'm told there are sites which list them by serial#. Maybe one of you know.