On the original 70 valve covers the pcv went in the pass side at the rear and on the 80s mustang valve covers the pcv is on the drivers side in the front,it has a holley carb and the pcv port is close to the original 1970 location so a short hose was used but when I installed the later valve covers I had to use a 2 foot long hose since there was no other place to hook up the hose for the pcv. The mustang got the vacumn for the pcv from the carb spacer in the front so I will try to duplicate it with a aftermarket carb spacer as the mustang carb spacer is made for a egr which I dont want to use,it seems strange that a longer hose would lean the motor but it did.