how many calatic converters are on this year truck

Depending on the engine but normally 3.

For all engines, except for the 6.0L V8 I'm seeing one catalytic converter assembly consisting of two converters. One for each side of the engine, which can be replaced individually. The 6.0L has two separate catalytic converters, one on each exhaust pipe exiting the engine. When replacing the catalytic converter(s) you MUST know what emission control system you have! The emissions decal under the hood will tell you. Replacing the converter with one for the wrong emissions system will only result in the P0420 code returning very soon! Hope that helps! Jim