I have a 1973 Dodge Charger I recently purchased. The block has this casting number, 3698830 440T Additionally these numbers are on the pad at the top of the block on the drivers side of the motor J440TX below that 49 2. My reseach indicates this was either a truck or motorhome engine. Is there a way to determine what year this motor was manufactured? When I pulled the plugs currently in it they are the peanut plugs 5/8". I am also getting some conflicting information on the correct plug for the motor. It has Autolite 24 installed presently. Thank you for your help
J440 indicates a 1973 model year engine. The "T" dunno. X commonly indicates a .010" crankshaft. The heads with the taper seal 5/8 plug were used on motorhome engines when they drilled two extra water passage holes in the block and cylinder head on each side of the spark plug. Maybe those heads are original to that engine and maybe not.