I replaced the distributor cap but i think the cat might be going bad on it. If I cut off the cats will I burn up a valve because of the suction? Will it be in my best interest to weld two pipes on there and just run it straight back?

 

Might be better off moving this to GM tech. Where are the cats on the Silverado? Does it have two or just one in the extension pipe? If you have one of those exhaust manifold/cat converter deals, I'd be careful about chopping it off. It might be too short and you'll cook a valve.

Why do you think the cat is going bad anyway? What are the symptoms of the truck?