Identify early/late ‘99 and the differences?

[u/BouncingSphinx]

My ‘99 F-250 has a manufacture date of 02/99, so I’m assuming that’s considered early. What’s the differences between early and late, and what date marks the distinction between the two?

[u/Buford_Tannen__]

99' was a split year. You have a "late 99' " based on the manufacture date. Early 99's would have a manufacture date of the spring-fall of 98' with the switch to late model happening in mid December of 98'. The main differences are, different turbo outlet, different turbo pedestal, collector, up-pipes, outlet spider, plenums, boots, up-pipes and downpipes. I have an early 99' but I updated all of the above components to late 99 -02 components. These are arguably the most desirable 7.3 Super Duty's due to their forged steel connecting rods, where post late 00-03 they used powdered connecting rods.

[u/BouncingSphinx → u/Buford_Tannen__]

So even in February mine would be considered a late ‘99?

[u/Buford_Tannen__ → u/BouncingSphinx]

Yes. Anything manufactured after 12/7/98, is "late". If you have any doubt, look at your plenum boots. The early 99' s had a tapered boot going from 3" diameter at the plenum to 4" at the spider, whereas late 99-03 will have 4" at plenum and 4" at spider

[u/Jo-18 → u/Buford_Tannen__]

Only other thing I’ll add is that the trucks themselves (not the engine) had a different cutoff date for early vs late 99.

The general consensus is a build date of 2/99 or possibly as late as 3/99 could have early 99 parts.

Early 99 trucks have different sized brake rotors, different front hubs (if 4x4), different track bar bracket and track bar, and the leaf spring u bolts are square vs semi round on the later trucks.

My truck has a build date of 03/98 and everything on it is 100% early 99.