you do not need any guide plates.for 5/16 push rods. but you need to check the heads that the pushrods do not hit in the heads .they have cast slots in the heads somewhat a guid that the push rod runs thru the head. that holds the rocker track . the longer 1.6 will hold it the 3/8push rod at a dif angle then you need to drill out the guids / heads slots out and then you need guid plates and screw in studs the push rods need to be stock for the stock stuff to work that is 5/16 not 3/8 if you go 3/8 you will need much work. you allways should check the pushrod for the right length way to many things can throw this off and you can if they hit at the bottom of the slots with a small stone or bur in a dieginder just take out were it hits do not make it wide or your rocker will not track