External differences between cat 6nz and mbn engine?

Trying to find out what engine I have without paying someone to read the ecm. I was told by the person(dealer) I bought the truck from it was a 6nz. Talked to previous owner today and he said when he bought the truck the engine had either had an out of frame or engine replacement. He said this because the engine had been painted out of the truck, defining line between engine and transmission. Anyway that has got me to.thinking, what if they replaced the original 6nz with a mbn? How could you tell externally? And there are no tags or plates anywhere to tell me what it is? Also got me concerned because of the fuel mileage and it does not pull like I think it should.

 

I had a 2ws and the mbn had a module behind the fuel filter than ran the wastegate. The 2ws never had that. If im not mistaken the 6nz is the same.

 

Should be an engine serial number stamped on the passenger side of the block at the rear around the exhaust manifold

 

Well I have looked and looked. Only thing I can find is the block casting. 125-8850. Which doing a little research, says it is a c15,.6nz 3406e block. Can anybody dig up anything else? Also noticed on the ecm there is a decal that says this engine is epa/carb certified tampering with fuel settings will result in fine. Why would it be carb certified if it is a 6nz?

 

here is a picture of that decal I was referring to.

 

Is there a part# on turbo center section. 6nz used an or-7923 or a or-7310

 

has aftermarket turbo on it....borg warner 177148

 

I've got a 2ws and an MBN here. Let me know if there's something specific you want me to check if that will help.

 

My 6nz has the same decal. Carb had emissions regs back then too.

 

The MBN has the turbo waste gate line that runs around the head to a dump solenoid by the fuel filter housing.
also the s/n is stamped into the block on the right side near the rear, can be hard to find if lots of paint or rust is on the surface but is there.