After my 98, 4.0 V6 PUSHROD Ranger got wrecked by State Effing Farm, the thing that decided me against replacing it with a newer one was the cam drive replacement. Crank drives jack shaft which runs through the block where the old cam rode. second chain drives from front of jackshaft to one cam on front. Same drive is on REAR of opposite head, so a REAR chain drives from the jackshaft to the second head. Some? All? engines have a balance shaft so there are FOUR timing chains and of course one in the rear...........you pull the engine.
