Firewall issues

[RoadRashNinja]

1) I have a 1994 C3500 ECLBD that had a 350 in it originally. I just dropped in my 454 and wanted to use the tall Edelbrock Elite Valve covers. On the drivers side it fits fine with enough clearance, but on the passenger side, it hits the firewall. What is the best way to make room to fit my tall covers? I tried a block of wood and a hammer, but it didn't make a dent, so I'm not sure what's behind it. The part in question is to the right of the A/C tank, and under my computer. There's a crease(bend) in the metal protruding out, that now needs to protrude in.

I can provide pics if necessary to find out what kind of damage I'm looking at if I start to hit it with a mallet instead of just a claw hammer.

2) What is the best way to cut a hole in my hood to clear my engine's intake assembly? The engine is a 8-71 454 with two 454 tbi units on top, with some type of intake scoop.

Thanks in Advance.