The firing order changed from 15426378 to 13726548 because the camshaft dictates the firing order and the camshaft was chosen for the then-new H.O. 5.0L in '82 due to time contraints and availability, nothing more. Engineers in charge of developing the H.O. 5.0L engine for the Mustang wanted to afford it a better camshaft than what was currently being used but could not justify tooling a brand-new one so they sourced one from a previous 351W application (D3OE-6250-AA which is a '73 Torino application, NOT marine).
Last edited by FoxChassis; 11-04-2002 at 04:51 PM.