Im checking out a 04 in a few hours. Im wondering how you tell 2004s and 2004.5s apart. I know I for sure what a 600. Im also checking out a 2006 with 10k on it. Is there anything I should look out for on newer trucks?

 

Look under the passenger seat to see if there's a cat or not or a piece of pipe where the cat used to be in the exhaust system. You can also pop the hood and the "HP" tag on the drivers side of the valve cover will read 305 on an 04, 325 on a 04.5.

Good Luck

 

After having several of both, if I were going to choose between the two I'd prefer the 03'-04' over the 04.5'. Fuel economy was much better on the 250/460 or 305/555 vs. the 325/600 or 325/610.