Engine/Transmission (1998.5 - 2002) Distinguishing between an SO and HO

[FosterW]

Is there a way to tell the difference between an SO pump and an HO pump?



I have a hunch mine might have been replaced by the previous owner and I would like to know what I've got.

 

[Cigar John]

SO will have 027 stamped on the data plate ,HO is 028

 

[FosterW]

Thanks I got the same answer on CompD. Looks like I have an SO on my HO!

 

[WestTN]

The SO can deliver more fuel than the HO.

 

[darkhorse]

The SO has more capacity at the top end but discharges with lower pressure.

 

[AllianceDiesel]

my truck ran like a snail with the so on there, put the ho on and it runs 100x better, I have heard though that if you put a so pump that has the wire tapped like with an adrenaline it runs a lot better, I have a spare so pump in my garage that Im gonna try