Edelbrock heads I’ve been told are still being cast in California. Edelbrock is famous for making an ugly “plunge cut” on their heads. Do not buy Edelbrock heads bare unless you are capable of fitting the valve guides. Both heads respond nicely to a nice racier valve job. Speedmaster heads come with 10 degree retainers and keepers while Edelbrock after all these years still come with crap 7 degree stuff. The Speedmaster castings are 10 times nicer as is the valve guide fit. The Speedmaster heads flow a few cfm better out of the box. I never check spring pressure out of the box as I always set them up after I’m done but from member spring pressure is on the low side.
