The 300 straight six (truck engine) was one of the best engines if not the best made by Ford. It was derived from the 240 which was installed in full size Galaxies I think starting in 1965 thru like 1968 or so. I believe the 300 came out in 67 as my ex father in law had a 67 F100 with it in it. Last year was 1996 and many pick ups and vans had them, as I had a 1996 E-150 conversion van with it. I also owned a 65 and 66 Galaxie both with 240's. They were great engines. The early Mustangs with straight sixes were a different engine, which came from the Falcon/Maverick/Fairmont, 177, 200, 250. I think you could probably put a 300 in a 01 but would be a bit of a challenge, and personally I ask why?? Anyway good luck in what you decide.