I crawled under my 97 to measure, and it APPEARS that I have 2.25 to cats, 2.25 off Y to back, tail pipes after they split seemed to be 2 inch, but no real good place to measure that I could get to. No 2.5 found anywhere, and now that I look at it, the dynomax setup seems like it will be way better than stock, I don't need stainless steel, aluminized steel will last forever here, the trick is to paint the welds. I need to spend some time under it and look at it closer and figure out what I want to do.
Now that is a 97 with a 4.6, not a 93 with a 302, there could obviously be differences. And the pipe after the split in the back might be 2.25, I couldn't get to it real well, I was doing this on my lunch break on a hot car
The 1995 NVMA thingy posted on SCCOA (I wish I could find it for 97) shows:
3.8 NA - 2 inch all the way
3.8 SC - 2 inch from manifold->2.25 intermediate->2 inch tailpipe (which could be after the muffler?)
4.6 NA - 2.25 from manifold->2.25 intermediate->2 inch tailpipe (which could be after the muffler?)
With variations for California, Manual tranny, that sort of thing.