What exactly is the difference between a 3500 and a 4500? The GVWR and GCWR seems to be the same. The engine is the same. The 4500 has duallies but so do some of the 3500 cutaways. Is it just the label on the door?

 

I think the 4500 is a cutaway

 

That's whats confusing me; I can get the 3500 as a cutaway dually too. :headscratch:

 

The Savana 4500 is 1900 lbs more gvw. Heavier suspensions etc. The sierra/silverado 4500 cab and chassis also have higher load specs.
They are commercial chassis options.