67mustang302

The main purpose of the dowl pin is to align the gear properly with the cam, otherwise you could install the timing chain and if you didn't degree the cam or check to make sure if it were aligned, have timing WAY off. So the dowl pin just makes putting the gear on the cam easy. The other thing with pins, is if you use the long one and run a mech fuel pump, the eccentric might not seat properly. Also my Crane cam instructions for the 5.0 I'm building now say the short pin is for 80 and later engines.