According to what I can find searching the net the 98 model year gained 15hp and 10lbft. Where was this increase in power made?
Computer tuning or was there a different cam, intake, etc?
Reason I ask is I am looking at a 97 that has had a 5.9 swapped in place of the 5.2 and they think they got the engine from a 98 or 99. How can I identify which one I have and if its a 98+ would I have the higher power output?

Other footnote that may throw all of this out.... or may not matter at all is he says it still has the 97 5.2 computer.
This is a 5spd 1500 4x4 if it matters.

 

Block casting numbers might tell you what year the motor is. I think most of the power gain was from a slightly different intake design (the center divider went away), and PCM programming. I would get the PCM flashed for the 5.9 though. SCT from Hemifever would be just what you would need.

 

Ok so basically trying to decode it is the only way I might be able to tell..... is the intake visibly different with out pulling anything apart?

Will the tune help much for everyday driving and mild trail riding?
It runs good and smooth the way it is and he says he gets about 16mpg on the hiway with it with 33's and 3.55's so I thought that isn't too bad considering we live in a mountainous area.

 

Manifold differences are:

94-95 had EGR, and center divider, two coolant temp sensors.
96-97 had no egr, (maybe a block off plate) center divider, two sensors.
98 and up had no egr, or block off plate... no center divider, and one temp sensor.

 

Ok so most likely if this truck still has the 97 5.2 computer it most likely has the 96-97 engine or atleast the original intake to retain the sensors for the computer to read from?
Was the intake the actual power increase?

 

It may have been a contributor, but, I suspect most of the power gain was from programming. There is still a fair bit of power to be had from a tuner though. Just getting rid of Torque Management frees up some power.

 

Sounds good.
Its had a little exhaust work but no headers yet. Do shorty headers make much improvement on these engines?

 

When I was trying to identify motors, I found numbers stamped on the side of the block, Passenger side. They looked to be a date code, 10 04 98 with each number separated with a rivet of some sort. So October 4th, 1998. Something to look for. You will have to climb under the truck to see it.

 

Thanks, it gives me an idea where to look.

 

On there own no, used in conjunction with other mods yes.

edit: let me rephrase, on there own nothing you would feel.