I decided to fabricate a pushrod tunnel cover from a single sheet of aluminum rather than using the Z brackets and sheetmetal as in the plans. Here, I'm fitting a paper template to check the fit.

The angle at the back end is close...not perfect yet.

Similar situation at the front end.

Template #2.

Still not a perfect fit.

Template #3. Good fit.

Transferring the layout to a piece of .050 sheet metal.