Will self aligning rocker arms work on an older style head?

I think so. You need to be careful about the particular heads you are using though. There are 3 ways that the rockers are aligned to stay on the valve. The old style was the pushrod hole in the head would hold the pushrod straight. Sometimes these are drilled oversize, and guideplates are used instead. Or, the engine uses self-aligning rockers.

You need to be sure that you only use ONE of these methods.