Not alot of talk out there about either topic but its just some general reading material that may or may not be helpful... -Front Covers Because the Modular engines are used in so many applications, there are quite a few styles of front covers. Passenger car covers differ from truck covers and van covers are similar only to themselves. Likewise, the Mustang covers are different altogether and even from year-to-year. Some covers used 8mm bolts, while others use 10mm bolts. So it's important to keep the cover with the block. When building an engine from scratch, the only way to ensure that you have the proper cover is to trial fit. Then you must be certain that the engine accessories will attach. -Underdrive Pulleys Aftermarket pulleys are popular among Mustang owners. The 1996-98 pulleys are of one design, but like most other parts on the Mod engines, they changed with time. Thus, the 1999 design is different, and sometime during the 2001 production run, Ford changed the water pump design again, requiring a different offset in the water pump pulley. Therefore, there are many distinct water pump underdrive pulleys depending on whether you have a 1996-98, a 1999-early 2001 or a late 2001-present engine.