valve cover clearance

Ok,
I have been meaning to check the clearance awhile for my MT valve covers I bought to see if they would fit. I need to buy a couple of grommets so I can run them.

As you can see, they fit in my 69 383-s sporting a 440+6. I would say there is a quarter inch clearance between the motor and the fins of the valve cover.

Sorry to hi jack but may help others. How much shorter would blower motor need to be to clear towards the back of the valve cover?