Study all the different parts# books, Ford Performance by Pat Ganahl, The Ford High Performance Parts Interchange by Goerge Reid, Ford's Official 5.0 Mustang book by Al Kirschenbaum ( put out by Ford Racing) And lots of hands on experience over the last 30 years, to weed out the mistakes in the aforementioned books. The only one of the above that I DO rely on 99% is the Ford 5.0 book above, the info in it came straight from Ford. The other two DO have mistakes in them, but overall much of the info in them is useful. There are other books too that I've read, but can't recall them off hand.