small block cyl head question

That's the key. Decide where you want it to run. the low side would require more $$$, likely lots more because a stock block is at the limit there.

The RHS LA-x head Brian sells can easily get you in the 10's with a smart stroker build. The car could use a diet and that makes it easier.

ET is chassis so it needs to be up to the task.

Yep.