6.9 identification

[Ggg]

Is there any reliable way to identify a 6.9 from a 7.3 by looking at it in the truck?

 

[zigg]

There's a few actually. The first, most obvious is to find the serial number, and it will say 6.9...or 7.3... The block serial number is located on a little flat spot on the top of the engine just to the drivers side of the injection pump housing, between the housing and the drivers head, right at the front of the engine. The second most obvious is the size of the head bolts that can readily be seen. The 6.9 uses 7/16ths with 12pt socket, and the 7.3 uses larger 1/2" with 12 pt socket. There are others, but those 2 should be easy and obvious...

Zigg