[chopper]

With the wall thickness of the cast aluminum valve covers, you should be able to just grind down a little of the area around where the springs are contacting the covers without causing any further problems. I have a set of the old cast valve covers on my car and I initially had a little bit of interference from the outboard stands. I just took off a bit of the material with a Dremel tool and have had no problems with the covers.

I guess I'm just a bit surprised that you are having that kind of problem with the exhaust valves on just the two inner cylinders on one side. Just for arguments sake, who made the valve covers? Have you checked the other bank to make sure there are no problems on that side?