
It's pretty hard to tell 2.5 to 2.6 or 2.8 to 3.0 Usually 2.8+ trucks are complete frames ect while 2.5 and 2.6 are frame on trucks.
Limitations as far as fuel and additives are about the same throughout until you get in open diesel (outlaw in some states) The only big difference is the inlet size of the turbocharger 2.5" to 3.0" 95% of the pulling associations are single injection pump, no water/meth, no nos, no propane