2003 Peterbilt 387

Hopefully it's a 6NZ pre-fix and not MBN? Never cared for 387's had 3 different ones including brand new '03 ISX powered. Plastic rattle trucks right off the assembly line.

 

In 2003, there were different versons of the CAT C-15 . The ones with serial numberd 6nz are the ones you want.
The engines that came after the 6nz are known as bridge engines. They have a single turbo like a 6nz, but they are different and are known for poor fuel economy. If you are gonna buy an old truck, make sure you avoid any emissions junk. Avoid egr.

 

where is it located and what do the want for it. i just traded mine in 4 months ago in ill with a 6nz.