I know that as a general rule everything 1995 and earlier is OBD I, and everything after 1996 is OBD II, but I've read some contention on some finer points regarding this in Ford trucks, especially the 1996, 1997 and 1998 year model F250 HD, F350, and larger trucks. It seems even more confusing when you look at the 460, and when you get into California emissions VS standard emissions. Please note I am referring ONLY to the Old Body Style (OBS) trucks, as illustrated in the attached picture below, and only the 4.9L, 5.0L, 5.8L, 7.5L, and 7.3L Powerstroke. Not the goofy assed taurus with a truck bed bull**** F150/ F250 light duty, and sure as hell not the 4.2L, 4.6L, 5.4L or 6.8L. Please, let that be the last mention of them. Also cross posted this here: http://www.pirate4x4.com/forum/showthread.php?t=1059596

In the 1996 F150, are all engines OBD 2?

In the 1996 and 1997 F250 HD, which engines are OBD 1 and which are OBD 2?

In the 1996-1998 F350, which engines are OBD 1, and which are OBD 2?

Thanks in advance, and I will continue to scour the web, as I have for the past 2 hours in search of legit answers.

 

The last 5.0L F-series that was OBD 1 was 1995.

1996 5.8L Over 8500 GVW & 7.5L Over 14,000 GVW, 49 States & 7.5L Super Duty 50 States were OBD 1.

1997 5.8L/7.5L (49 States Or Super Duty) were OBD 1.
1997 5.8L/7.5L California Except Super Duty were OBD 2.

1998 there were no OBD 1 trucks. The F53 sold in 1998 was a 1997 with an OBD 1 system.
I do not show a 1998 F350 either in 1998 so Ford may have also sold the 1997 F350 in 1998. If it had a 460 (7.5L) engine in it in 1998 it was a 1997 with OBD 1.

 

The diesels are OBD-II from 96 on. If you have a 94.5-95 Powerstroke, you can get OBD-II by swapping in a 96-97 ECU, reportedly.