What is the difference between a 5.9 and a 6.7 dodge diesel?

mL of displacement

the engines displacement. the 6.7 litre will tow more,carry a heavier load and also burn more fuel. if you are not going to tow or use the truck for anything other than a grocery getter id go with the 5.9

all they above is correct but if you have the coin go for the big one you ll never know when you'll have to save a damsel in distress, but if you want a real truck purchase a Ford

theres not much difference mechanically since the 6.7 is an over bored 5.9. but what is different is the emissions.the 6.7 is far cleaner than the 5.9,as it already meets 2010 emissions standards.this is accomplished primarily through the exhaust system,and higher pressure fuel injectors.the 5.9 will not be availble as the 6.7 replaces it to reimburse for bio diesel. it does but accomplish better fuel economy,and better power output than the 5.9, or offerings from ford and isuzu chevrolet's duramax is really an isuzu engine. isuzu diesels are problem prone when they start to get some mileage on them