Originally Posted by KarTek

Early or late '99? Early '99's have a build date of December '98 or earlier. Also have a Powerstroke V8 fender badge.

Cut and pasted from a list found on the Interweb:

Early 99 has a wicked wheel in it from the factory.

The E-99 has 130cc(AB code) injectors and the later 99-03 has 140cc(AD code) injectors.

The E-99 has 2" intake runners. The later 99-03 has 3" intake runners.

The E-99 has a 15* swash plate HPOP. The later 99-03 has a 17* swash plate HPOP.

The E-99 has one glow plug relay. The later 99-03 has one glow plug relay and one air intake heater relay side by side. Both relays are on the passenger side valve cover toward the front of the truck.

The E-99 has a totally different air filter that is not inter changeable with the later 99-03. But you can put the late 99 air cleaner assembly in the E-99 truck.

The E-99 track rod has smaller mounting bolts than the later 99-03.

The E-99 has shallower rotors than the later 99-03.

The E-99 has shorter hub-bearings than the later 99-03.

The E-99 front axle U bolts are square where they go over the spring pack. The later 99 U bolts are round.

The E-99 has a different pitman arm than the later 99-03.

The E-99 does not have the AIH like the later 99-03.

The E-99 does not have the automatic transmission fluid cooler in the radiator.

The E-99 has no indicator light showing that "cruise" is on. Later 99-03 has a cruise light that will come on when you set the cruise control. Some of the E-99 trucks have this light in the dash already. A newer PCM(Yes it will plug in and will run better too) must be used to make the cruise light illuminate. It is a green light on the right side edge, half way up.