I started the swap earlier, im gonna wait till it cools down a little outside to proceed. I have only taken the bumper off so far. Will post pics as I progress.

Just filled up for the first time since the swap and got 19.1 so I'm happy!

U suck 14.1 for me today on my auto Ready to help me g56 it ? Hahaha

Anytime John! You should come to the next pull, its July 27 at Wachula rodeo arena. You can ride down with me if you want.

Just filled up for the first time since the swap and got 19.1 so I'm happy!

Long ways from ISX yet... (25-27 MPG) I'm still above 20 MPG with a VP44 & +50HP Injectors... Time to tune that thing in...

U suck 14.1 for me today on my auto Ready to help me g56 it ? Hahaha

Is that city driving? Unloaded/loaded? If I run a tank without being hooked to anything I can top 20 mpg with an auto, but virtually all of my driving is rural country roads. Once I get up to speed, I'll lock the converter into 3rd or 4th depending on speed/load conditions.

My pump and injectors are set up a bit different than isx too. I am tickled to death with the mileage so far but it does need some tuning. This tank was unloaded with mixed city/hwy and playing mixed in. I doubt I will ever see mid twenty's with these pump mods and 7x.010 injectables.

I doubt I will ever see mid twenty's with these pump mods and 7x.010 injectables.

And 4 wheel drive. Its apples to oranges comparing fuel mileage with these 2nd gens in that aspect. I know a guy with a 00 24v 2x4 3500 dually and he runs circles around me in mileage. Glad to see your up and running and happy with it! That's all that really matters!

low end grunt, like straight out of the floor grunt where you can put it in gear and let the clutch out was gone, I hate smoke so I spent weeks tuning the afc to get it clean which made it laggy, mileage with the vp on the highway was never under 18 usually closer to 20, p7100 never got better than 15, egt's became hard to control, it was a monster when my foot was on the floor, and a turd the rest of the time. I blame most of it on the static timing, it makes everything a comprimise. It did make 560/1198 with a little 62mm turbo, so like I said it ran good full tilt. It just wasn't fun to drive anymore and pulling a trailer was a nightmare. I've still got the engine, no idea what I'll do with it though.

Sounds like too much timing for how you used it.

Remember both Whitelightning and myself are both 4WD truck so that is a apple to apple compare. But now fuel system wise and injectors tosses a monkey wrench in. ISX is a hard one to catch in MPG's I've touch 25 MPG once and only once. But over my life of the fuel logs I typically can hold 20-23 MPG on the open road, 16-18 hauling firewood, and 13-14 hauling the RV. But then you also have to consider what you building for and why. More HP/TQ the lower typically the MPG's will get. There is those rare few that can get a good mix of both.

27 is 55mph highway driving and takes a little work. 25 is easy enough. 23 is my typical city/highway. My tires are so small that my RPM is really high as in 2100 RPM at 70 so by then I'm at 21MPG which has been the same every time I have done 70. Between the high RPM and modest timing I run (13-14), it doesn't bode well for high RPM. I just hate losing the low end torque when I rack the timing up. With an auto tranny I would throw it at 15.5* in a heartbeat.

Im running about 17.5* timing, shot for 18 but it kept back off a hair. Also have 34" tires, large injectors, .024 delivery valves, star wheel is 10 clicks from all the way forward, 100ish plate, and modded afc slid full forward.

Sounds like too much timing for how you used it.

that's what I thought too, but I was only running 21.5º, I backed it off as far as 16º which helped the low end grunt but my EGT's got out of hand just trying to pull my trailer down the road. The caveat here is that I did a full engine build at the same time so some other factor could be the issue too. Piston choice or head porting are possibilities that pop into my head. Anytime I mentioned the issues I was having the guy that was coaching me on the build just said "welcome to P-pumps" I've regretted converting mine since the first time I fired it up.

21.5° is a bit much for anything but a race/DD motor, as you noticed it sucked for towing. 16° is closer to a better timing and should have ran really good from 2200-2500 rpms when towing. Too high of EGT's could have been turbo/injectors/etc.

well the VP from the factory will run up to 24º and I had mine running over 27º at peak, not trying to argue with you just what I recall.Had 5 different sets of injectors in it, 6 different P-7100's, three heads, and two sets of turbo's, one set was my old 64/65/14 over an S475 with a race cover, the other was a 62/71/14 single. I loved the compounds with my VP, never got them running right after the change and I'm still not entirely sure how but they ended up on my buddies rig and I ended up with his 62 that I ran for a while.I don't think the EGT issue is injectors, my current (and best) set were custom built for me by Weston and run clean unless I get into the pedal, they are what killed my part throttle haze, the turbo could have been an issue, we'll see once I find something to put the engine in since that turbo has been sold.

Timing on the VP is different thou, peak to peak yes the VP runs more, but it's not running 24° when your at 1500 rpms and 40% throttle trying to get a load moving. Neither of those turbo setups sound great for towing, the twins would run good once spooled but with a trailer in tow and 21.5° of timing on a P-pump I think they would be slow to spool. It's hard to say, there are a lot of variables. P-pumps have peaked torque curves, VP's and CR's have flat torque curves. It's all about timing. My current tune peaks at 20° of timing, but at 2000 rpms and WOT it's less than 12° and there is about 850 ft/lbs of torque being made there. Yes, I know the pilot and high pressure reduce ignition delay, but it's still not a lot of timing. For me to run 27° of timing on my truck I would have to really increase the fueling, and even then it would only be at high rpms.

Like you said, lots of variables, I LOVED those twins for towing with my VP, absolutely loved them, I grossed over 30,000 several times and I rarely saw 1000º and never over 1100º on long hard hills with 110 HP injectors, HRVP, redline box, edge EZ, and a smarty, they were fully lit by 1800 rpm and pulled hard to 3900 rpmwith the vp.I tried timing all over the place, rpms all over the place, it just never seemed to have a sweet spot no matter what I did. I keep wondering if I dropped too much compression, but many I talked to have dropped the same amount and not had any of those issues. Been considering changing back to a high compression piston to see if it helps.

Like you said, lots of variables, I LOVED those twins for towing with my VP, absolutely loved them, I grossed over 30,000 several times and I rarely saw 1000º and never over 1100º on long hard hills with 110 HP injectors, HRVP, redline box, edge EZ, and a smarty, they were fully lit by 1800 rpm and pulled hard to 3900 rpmwith the vp. I tried timing all over the place, rpms all over the place, it just never seemed to have a sweet spot no matter what I did. I keep wondering if I dropped too much compression, but many I talked to have dropped the same amount and not had any of those issues. Been considering changing back to a high compression piston to see if it helps.

How low is your compression?

S.O. piston (16.3:1) with 0.030" off the top.

How low does that make it? Doesn't seem too low, thou it will have an effect at partial loads.

I think* 15:1 with a stock gasket and 14.5 with a .020" thicker gasket (I'm currently running stock) but that's just a SWAG.