The 83 4502974 stamping could very well be a rebuilder's stamp. Did you verify if your engine is US built?
By the way the 3834812 Casting Number is for more than one year.
You can veify the year by the Date Code. If the engine is out or if you can get to the back of the engine on the drivers side (on the flat surface near the bell housing), look for the Date Code. It will have some numbers, but will start with a letter.
Last edited by 62BillT; 10-30-2008 at 04:37 PM.