rico334

Reading over some of the posts here has me confused. I have determined that there appears to be a 555 and a 600 when some talk about the Cummins engines.

Mine is an '03 and there is a sticker on the side of the valve cover that refers to it as a 305. Whats all this mean and which do I have, the 555 or 600?

Thanks,
Rick

nirion

The 03/04 engines were 305hp/555lb-ft. In 04.5, they introduced the "Cummins 600" with 325hp/600lb-ft. But new for 05 is an extra 10lb-ft to reclaim the most torque title.

So in short, yours is a 305/555 engine.

Nick

Venom617

You have the 555 engine i.e. 555 lb ft torque 305 hp

the 600 is 600 lb ft torque with 325 hp.

Really they look the same from the outside, not a whole lot of difference, but on the inside they have changed.

The 600 uses a redesigned piston that helps meet the emissions standard that all trucks will have to meet I believe by 2006.

Also the injectors where changed. The old ones such as the ones on your truck have 8 lazer cut nozzle holes made in each injector. On the 600's they changed that to 5 slightley larger lazer cut nozzle holes in each injector.

Also the wastegate on the Turbo Charger is now computer controlled as before the 600 it was not, so that pretty much sums up the balk of the major changes.

bhoeffner

The 600 also has a 4" exhaust from turbo down pipe all the way back.

nebuniRAM

And a big EGG in the back https://www.dieseltruckresource.com/...hreadid=52783#