Pre emissions truck

Welllllll in reality low NOx ran back into the 90s. So technically that’s still emissions compliance. But yes, lower NOx standards were pinned on heavy duty engines in 2003, with the introduction of EGR and what not.

 

I've been told by some 6NZ guys to avoid the MBN or "bridge" engines. Apparently they were real dogs from the factory.

 

Any cat motor except for the SDP prefix is pretty easy to tune and make run great.
6nz is the best non acert
The acert's are arguably a better platform but come with a little more BS. Like IVAs and compound turbos (i like the compound turbos, i ran a set on my 6nz). But they can be made into really strong motors!
The MBN in stock form is a dog but with some simple tuning and changing the wastegate control line they will run great.
Even the SDPs can be made to run good it just takes more work

 

My old man had a 475 hp MBN brand new and once the bugs were worked out of it in the first month or 2 it was fine. 120k lb gross off highway every day no problem at all.

 

Pre 2004 generally - don’t overlook an N14 or 12.7 S60 - both are still strong and serviceable.

 

I read it is 2007 for pre-emission, and I would almost guarantee Congress is racing to change that. I thought it was generally before 2000, and why 80s and 90s trucks are so popular, but I think soon, ALL trucks will have to comply to emission standards. Pre-emission trucks still comprise a small amount of trucks actually on the road. An older CAT 3406B is still the best motor you could have, and is considered a "pre-emission" motor. Watch out in California with one, I think.
Why Pre-Emission is Still King 20 Years Later: What You Need to Know

 

If that actually becomes law then I hope someone will sue on the grounds that it is an ex post facto law.

 

An old KW or Pete with a red engine under the hood is just wrong on every level.