I"m thinking of getting a used engine from a wrecker but would rather install the Fast engine rather then the Soot engine, what changes would i have to make for the swap to work with the 95 LD 2500 4 x 4?:D

You could use the entire 'S' engine the way it is, block off the exhaust ports to the lower intake, grind all the webbing out of the upper intake and change to an 'F' PROM, and it would basically be an 'F' that still looks like an 'S'.
If you can find the upper and lower intakes from an 'F' it would be a very mild improvement. Changing to the 'F' PROM is the important thing.

The wireing for the S can be just left hanging then with the F prom?
I was looking at picking up an entire engine, the reason for F or S. Don't have to change any parts around, just bolt it up, start it up and then sell it..... to you $$$.

So lets say one where to convert over to an F from an S. In Arizona we have emissions every year and one of the checks is the inspection for a soot trap based on the S in the VIN. How would this work with the Motor Vehicle Division since the VIN will still have the S but with an F engine installed? Has anyone dealt with this at all?

The 'F' engines have soot traps in the exhaust (at least mine does, dang it!:( ). Or I guess I'm off base here, do 'S' variants have another trap somewhere from the factory courtesy of GM GoodMonkeyWrench?Censored

My F still had the soot box on it too, i could even see through it after 150,000 km's

I can see through mine REAL easy

S & F parts are direectly interchangeable, one thing to keep in mind before parting with S stuff, if your vehicle came as a S VIN truck, if rumors are true next year emission hounds are supposed to get tougher 2006 from what I recall is supposed to be year it happens. You make need to be S configured to pass inspection, to go S to F, main difference is the PCM, year to year match those are easily interchanged once theft deterrent 97+ IIRC is taught to the swapped in PCM. S intake even with EGR cappped as I do in my "off road" configuration does still have hot gas flowing in the intake, temporary solution is to install a F set of intake gaskets, better solution is swap to F upper intake without ports(but then you would not be EPA compliant).

I just block off EGR with a shim when I'm offroading, only time I think the EGR in intake hurts much is when checking max power on a dyno, another thing on some S engines is precups in heads have smaller openings, which also another thing that probably does not amount to much power loss. So S into F no big deal, if you "run the wild side" with the law put all your top end F stuff on a S block, just hang on to it though if your VIN requires the S stuff to be present and they do start cracking down nationally as rumored. I think you could swap to F heads for the larger precups and run S intake no problem if you had to and it would not make any difference on a exhaust sniffer or visual check..

better solution is swap to F upper intake without ports
Don't you mean lower? To many F's & S's in your post, i'm getting confused...
You're also talking entire PCM swap, can i not just swap in a 95 F prom to the PCM or does the whole thing need a swap?

Don't have to change any parts around, just bolt it up, start it up and then sell it..... to you $$$.

If you're just going to sell the rig, then why bother? But, if you're in it for more power, then swap in a HD non-egr lower intake manifold, then just for the appearance use the egr upper intake manifold. Port the upper, removing the material around the ring, or get rid of the ring all-together, and bolt a plate on the bottom side of the EGR valve. That way you can have the valve present and looking like it can actually do something. When in reality, there isn't any exaust gasses in the intake to supply the EGR, because of the HD intake below. Just a thought...

Actually upper & lower my bad, or as CD had it for appearances could do EGR upper with F lower I guess I've got a F lower I might have to investigate that myself, Prom for those with prom PCMs, and PCMs for those with OBDII needing whole PCM.

So does that mean in theory, when I go for an upgraded prom I should just look for one for an F rather than use the code on my current one?

So OBDI PCM's have PROM's that can be swapped, but OBDII needs the whole PCM replaced????

ya, sucks for me-:t

This guy is wanting 20 bills for this. Would this work (going from S to F)?

http://i11.ebayimg.com/01/i/03/d3/46/98_1_b.JPG



http://i19.ebayimg.com/01/i/03/d3/48/95_1_b.JPG

Here's the description....

Pic is representative, you will receive similar unit in as good or better condition-I inspect every unit leaving here as I dont want to see them again!! Buy with confidence! Very nice intake manifold, off a HMMWV engine, fits either the 6.2 or 6.5 diesel GM engine, not sure which or both, Cast PN 23500011, this unit has nice threads for air horn to attach, Excellent used condition. No cracks, nicks or dings.

No the hummer one won't work it's circular on upper inlet, the GMC/Chevy one is a oval/hex shape, I'd shoot pics of my F lower but I'm away from it. I'm working in Bath Maine I finish tomorrow.

NVT MNT a F prom should work in yours and give a little more bump in performance, at least when I went S to F PCM before I reflashed I got a little more bump in performance.

OBDII 96+ requires reflashing not just chip changes.

S to F stock program on my OBDII 56mm to 63mm bump in fuel IIRC I suspect the OBDI chip will have similar fuel curves, the 1st reflash I ran was a BD reflash(Z IND) 76mm but driveability wise very little difference over just jumping up to a F stock so I sent the $600 BD flash back. The Heath reflash 80mm+ was night & day difference over the stock F & BD/Z Ind.

So OBDI PCM's have PROM's that can be swapped, but OBDII needs the whole PCM replaced????
Reflashed, but what I recommend is get a junkyard one for the reflash core, that way you can go back to stock, core charge if you want to keep stock PCM is $500-600, so that plus reflash fees, or get junkyard one for $75-150.

If you're in it for more power, then swap in a HD non-egr lower intake manifold, then just for the appearance use the egr upper intake manifold. Port the upper, removing the material around the ring, or get rid of the ring all-together, and bolt a plate on the bottom side of the EGR valve. That way you can have the valve present and looking like it can actually do something. When in reality, there isn't any exaust gasses in the intake to supply the EGR, because of the HD intake below. Just a thought...Exactly how I did mine, working on the PROM upgrade still, 'S' leaves much to be desired.

So can I go from an S to F PROM in an OBDI system?

Yes, fairly common and worthwhile upgrade for us LD guys

Cool, whereinhell do I get one?

GM dealer can give you a new updated one if you can provide a VIN for an 'F' truck with the same engine/tranny as yours.
Junk yard might have a wrecked truck with complete ECM.
Aftermarket performance chip guys can upgrade yours to an even higher output 'F' PROM.

Besides not looking at the EGR, what benefits does the F program have over the S program?

Cool, whereinhell do I get one? try a junkyard that is where I got my F PCM.

Besides not looking at the EGR, what benefits does the F program have over the S program?
Gotta read the whole thread to get benefit of what is poseted here 4 posts up I listed S to F improvements


S to F stock program on my OBDII 56mm to 63mm bump in fuel IIRC I suspect the OBDI chip will have similar fuel curves, the 1st reflash I ran was a BD reflash(Z IND) 76mm but driveability wise very little difference over just jumping up to a F stock so I sent the $600 BD flash back. The Heath reflash 80mm+ was night & day difference over the stock F & BD/Z Ind.

Sorry TD, read that a day or two ago and it slipped my memory.

So going from a stock S 56mm to a F Heath reflash 80mm PCM, I'd be flowing around 24mm more fuel. How is this on economy? I'd like have the power when I need it, but economy is in the back off my mind with the gas prices the way they are lately.

Economy? *snicker* I bet it does have more economy right up till your right foot discovers all that new power! http://www.dieselplace.com/forum/images/smilies/rolleyes.gif Kinda like how the 4" exhaust did my truck a world of good till I found out how good it sounds with the pedal pushed to the floor! http://www.dieselplace.com/forum/images/smilies/rockon.gif

):h Worried about gas prices for a Diesel Hmmnn me thinks you got bigger problems than wanting more fuel):h Sorry could not help myself, going to the Heath reflash allows for more fuel not that you got to use it, my mpg stayed the same, unless I put more pressure on right foot. For S to F PCM or chip is a nice bump in fuel 56 to 63 and a inexpensive way to get a little more grunt until; you can afford a reprogrammed chip or reflash.