[Rick Parker]

As Marcalan has hinted at, Ford used several different front dress packages, consisting of various front covers, water pumps and spacers for the alternators. It's easy to unknowingly mix and match components, the end result being a standard set of pulleys will not work. Occcasionally the mounting hub for the waterpump pully can be moved on the shaft (with a press or gear puller) to compensate for some small amounts of misalignment.

As a side note, some of the crankshaft gears from timing sets have a shoulder machined as part of the gear and this will cause the crank dampner to be moved further away from the engine.