with the 69 head there are sloted guide holes in the heads that hold s push rod tracking .less the boss,s been cut down and guild plate use with screw in studs then you drill the heads out were the sloted holes are in the heads .there is no need for self guided rockers for stock 69 heads if you used a +050 valve lock or a +100 valve spring retainer. the retainer will run in to the rocker arms you will need to run a shorter set up on valve spring that will let you run a retainer with no recess/off set . were locks are. or if a shorter spring can not be used then use a longer valves with retainers with no off set or set heads up with guide plates use STd/ non tracking roller rocker . many after market retainer have alot of off set to use a taller spring in the heads but on guided rocker you need the see that the valve stem is at the tallest part to clear rocker tip