OK so this question was brought up to me and I just assumed and went off about axle configurations and suspension not realizing there actually is a LD and HD 5.9L V8 motor, or is there?

Vin Code Z for LD 5.9L V8
Vin Code 5 for HD 5.9L V8

I've googled the crap out of this and come up with nothing, all sites I've found show the same bore/stroke, comp ration, hp numbers, same cam specs, same valve train specs, everything is the same. The only thing I've come up with so far is the the LD 5.9 is consistently followed by EML and with EMM for the HD 5.9 all i have found googling these terms is they are a production reference code and I have yet to find what the difference is. Any old time experts have a clue whats going on?

 

Pretty sure the only difference is in some kind of added cooling capacity.

 

And perhaps emissions..... I have read on the net.... that the HD engine had air injection, and dual cats...... No clue how much truth to that there is.

 

I had one guy suggest to me EGR any truth there maybe?

 

I have the HD and I don't have dual cats. I do know there is a difference supposedly in the fan clutch, other than that I don't know of any difference.

 

how do you know you have the HD just based off the VIN?

 

HD= heavy duty ?, as in a tow package that may include a larger radiator, a heavy duty fan clutch, and a external transmission cooler ?. I`m just guessing here, but its the only thing I could think of.

 

It was listed on my build-sheet.