OH thier different alright...
you can lump them into 3 catagories:
5.0L HO, 351W(himpy), 351M(oronic), 351C(atostrophic), 400 for the 1-3-7-2-6-5-4-8 firing order
289, 302, 352, 390, 427, 428, 429, 460 for the 1-5-4-2-6-3-7-8 firing order
FE = &%$#ing Engine