The Direct Connection engine book is also a way to increase performance on the cheap. The DC boys went to great lengths to weed out what worked and what didn't work. The chevy and Ford guy's in the 60's and 70's did not have a book like that to go to. Need to go 13's in the quarter and your car was so many pounds? Small or big block went through what was needed to do get there. most important was what was NOT needed. very handy book.