dimension

Hey guys, I have a 2004 1500 hemi. I'm trying to find out what size the pipe is between the exhaust manifold and the cat. I believe it's the downpipe?

I crunched my front bumper and I think I bent the bumper mounting plates that are welded to the frame. They look fine but appear to be slightly angled in the direction that the bumper was crunched. Before I mount a new bumper, I need to know the distance measurements of the plate mounting holes...