The difference between an 04 and 04.5
 

I guess my question is what is the difference and how can it be identified?

There are a few power outputs on the 04 cummins look for a tag on the valve cover that tells you the HP of the engine. 305hp is the HO there was also a SO engine.

on the 04.5 the tag on the valve cover will say 325hp. Plus the 04.5 has a 4inch exhaust turbo back vrs 3 1/2 on the 04. The 04.5 came with a factory cat. build date for the 04.5 I believe started in January of 04

hell i have an 04 built in late 03 and when it was stock it had 3 1/2in turbo back with a muffler and no cat. and my motor says 305. so that means high output? and it shows exactly 32psi with a smarty. so its def not a 04.5? and is it a 600 series?

04 have 305hp and 555tq, 3.5in exhuast.

04.5 have 325hp 610tq, 4in exhuast.

Otherwise there the same.

A stock, and unflashed, 04.5 is 325HP/600TQ...610TQ was a later 05 thing. DCX did reflash the early 04.5s for "performance and mileage" (a listed TSB) and that supposedly gained you the 610TQ...but I never saw an improvement, and if anything; the truck didn't run as well after the reflashing.

And I have read where guys claimed to have a later 04 with the 305HP HO with a factory 4-inch exhaust without a cat...

The biggest identifier of a 04.5 is the engine tag showing a rating of 325HP and the presence of the large catalytic converter in front of the muffler.

03 and 04 have triple nickel blocks :tu:

Look at the build date on the b pillar. 01-04 and later are the 325\610 engines or 04.5.

Huh???:humm: There is no difference in blocks in any of the CR's. Valves, valve seats, pistons, injectors, cams, and piston coolers are the differences depending on what motor and build date.