Wasn't 1973 the first and only year that Mopar used the Spool type K members in E bodies?
Also didn't they not offer BB in E bodies in 1973?
If the motor he used to out in his car came out of a C body it will have lower, deeper oil pan behind the center oil pan sump than B bodies did scopeshruggy

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)