olds a casting head questions

i bought a set of A casting 425 olds heads i plan on putting on a 455. my question is i want to convert them to adjustable valve train these heads are already redone what do i need to do ? the surface were the rocker arm studs go are flat and they have a funky looking stud already do i need to just unscrew the studs and put in new ones ? im new to this olds stuff i read were some A castings were adjustable from the factory and they all had a stud mount rocker most of the other heads i seen were for bolt down rockers . any other proublems i need to know of i got a real good deal in these heads or atleast i think so and maybe they already have been fixed the guy couldnt remember . are these a decent head ?.......thanks

 

the "a" casting is a good head for performance use. i'am not aware of any olds heads that have adjustable valve train. heres what you need to do. the pad has to be milled .110 for the guide plate. then drill the existing stud holes to 7/16-14. then you can install an ARP stud 7/16-14 bottom 3/8-24 or 7/16-20 top. use harland-sharp roller rockers. these are the best rockers for performance oldsmobile PERIOD. you need to mock up engine for the pushrod length. this is critical. use an isky adjustable guide plate. you also need a good quality pushrod and most likely will be custom length. if you need someone to do the work PM me i will be glad to help.

 

A better selection would be to find a set of B heads from a 66 425 Toro motor. They flow very well in stock condition and the pads do not have to be milled to use the Harland-Sharp adjustable rockers.