SILVERSLEEPER

Which motor was easier/ cheaper to modify and run in the 12's? Are the only difference's between the 2: the head, and the turbo wastegates?

acook

I would go HO

C Schomer

I don't remember all the improvements over the SO but the HO has another cooling nozzle for each piston and several key materials are harder, stronger or take higher temps. The HO also starts with bigger injectors, too. I would think the HO could take more beating. Craig

RAT_03

ho all the way

steve_o_reeno

how can you tell the diffrence between the trucks?

SILVERSLEEPER

will smarty come out with a hot version for the S.O.??

Forrest Nearing

Never heard this before... I have heard that they have higher compression. And the SO pump is capable of more power than the HO pump, so I was always under the impression the SO was a better starting point for a hot rod

abc4yew

When getting to the 12s ... cheaper is not the word to use. Many have made it with both engines. The only important difference is the cooling of the pistons...and more people have melted the pistons out of HO's than SO's so that is still up in the air... You will be modifying the injectors, turbo, transmission, and ECM program to get there so the other differences are moot....a 48re requires less mods to hold power than a 47re on early 03 SO's but AK RAM made it into the 12's with his 03 SO 47re.ks

KVD

Yeah who was that just made 1003HP on a 235 03 cail. truck. Was it don, cause I can't remember but I also remember in his sig. that he had another truck with 8XXHp and it was 235 cali. truck too.

He said at that point they even out and really doesn't make a difference. He also said he like the way the 235,250,305 horse motors drove with high horsepower over the 325 motors.

Forrest, you are thinkin about 98.5-02 trucks. On them trucks the HOs have smaller injectors and a smaller pump thats at a higher pressure than a SO.

The only difference's cummins list for the SO and HO trucks is the different coolin of the pistons and ECM tunin. I have never seen anything about different compression of parts that won't change from truck to truck. The SOs were supposed to be detuned of the 47re but for some reason there are 03 SO trucks with the 48re.

I've searched it on this forum and thats all I could find and some where through all that I found a link to the cummins and site and thats where the above info came from.

Nate-03 D

Both of the trucks sittin in my shed are 03 SO's w/ 48re's.

I keep hearing about these extra piston coolers, why would those not be on a SO? Do they affect emmisions or something? I don't even see why they even produced SO's for that crazy state.

I felt let down after I bought my truck and found out it was a SO, but my hopes got a little higher when I found out it had the 48re. lol It's a good truck though, runs just as good as anyother.

C Schomer

Someone posted all the improvements when the 305 first came out. There was about half a dozen things and they said it made the HO able to take higher egt,also. Maybe not! Craig

KVD

Nate the cail trucks are 235, then the SO are 250s and the HOs are 305.

Mine is the 250/47re and my buddy has the 305/48re and there no enough difference for me to trade mine for the difference in mileage and for what I'm gonna do it doesn't bother me one bit.

We run um stock (now his does have 35s) and he only had me but a headlight till 80. Maybe his 35s took up 55hp, maybe his truck is broke in more (115k mine with 52k). The trans doesn't bother me cause there are lots of high horse 2nd gen trucks with the 47re.

XLR8R

True - I had the 47RE in the '98 rebuilt with all new internals into a 49RE.

Nate-03 D

There seems to be way to many for me to keep track of. All I know is that I have a California truck w/ 235hp w/ the 48re. Im more then content after I added my BDTD. I wouldn't dare put it back on stock mode though, fells like im riding in a lifted Yugo.

CTDinMT

Mine is an 03 SO w/ NV4500. I'll never part with this truck. Another SO plus is fuel mileage. All of my friends with HO's want my truck...