Cat 3406 ID help

The needed number is stamped on the rh side of the engine block, pass side.

 

I've seen them stamped mid-block on the driver's side as well.

 

The serial number around that year won't always confirm if it's a C or B. Cat had alot of mixed up information on serial numbers around the 3ZJ prefix Era. 93ish. To know for sure,, its best to pull the pan and verify which crankshaft you actually have. A couple ways that might help get you closer to determining if its a B or C,

Look at the pump. Is it a 7E-5888 pump or 7W-3906?

Also, does it have the big square port exhaust manifold or is it a round port that reassembles a 3406E or C15?

 

If you call the dealer with the VIN number can't they tell you the exact model of the engine?

 

In the door jam it might have a tag somewhere that says “3406peec” or 3406atac” if it’s the later, it’s a 3ZJ engine the peec engine has an 8PN serial number..........unless the engine has been swapped.

 

B engine has 6 point head bolts C engine has 12 point bolts. They never put a b in a 1994 truck from the factory. I’ve talked to multiple people who claim that they have a B under their hood and in almost every instance, I lift the hood to find a C. B’s were obsolete by 1994.

 

Im aware of the head bolts. Good catch.

The 3ZJ could have been a B or C though. When Cat transferred alot of part numbers over to the new system in the early 90s, they had alot mixed up info on serial numbers. Thats why I asked which manifold or pump it had. Not only that, but that engine could be a transplant.