Ive got a 9 v10, it has dual cats, each one has a hard line going right into the middle of them?? I followed the line back up into the engine compartment and into a pully driven compressor or something? Plus there are no O2 sensors after the cats? Im kinda stumped on what it is?

 

if you have a 1994-1995 Ram V10
you may be looking at the extra air inlet lines on the dual catalytic converters
used on the 'Heavy Duty' version of the Magnum 5.9V8
which had a belt driven air pump supplying extra fresh air to the cats
for emissions purposes

they may have continued to use those style catalytic converters in later years too,
as I have not looked under later V10 models

if your model Ram is a 1996 or later
you may be eligible for free replacement of those catalytic converters
under the big Chrysler recall,
so it might be worth asking the dealership to check