[quote=Itoldyouso]Pat: Good info, so you don't always necessarily need guide plates when using roller rockers? I thought it was a matter of keeping them straight, and you needed the guide plates to act as a support.[quote] no what would keep the old ones straight? the head has the guid casted in a slot the new gm head have rocker arms with a slot in the rocker that holds it on track and with hp guid plates you must run harden pushrods and this would change if dart or any HO head with screw in studs may need guid plates