Interesting post. Im having 622 with PSO heads built and will need headers. It is a pump gas engine with shift points around 7000ish in a 72 Barracuda. Have been told TTI 2"-2 1/8" step with 3 1/2 collector will be enough. Im kinda skeptical about them. If need be ill have custom ones made.
PSO headed 632 from MM. Cracked cylinder, loose valve seats, low oil pressure, low cylinder pressure. ..... Now its a door stop....
