The catalytic convertor that's on there is of unknown origin and age.

When I bought the truck, the exhaust consisted of the original cat, a newer cat back where the muffler should have been, then a stupid little 'race' muffler not 6 inches off the back of the second cat.

When I had a new muffler installed, they took the second cat and replaced the stock one with it (the truck only has one cat now in the stock location).

There was a VERY noticeable difference in how the truck ran after doing this.

As for pinging, it hasn't pinged at all since I did the plenum and intake gasket (and when it did, it was only slight).

I'm going to get after it in a few minutes......