So just took the Utility Truck on a nice 800 mile interstate trip to pick up my NV4500 and Divorced NP205 set up for the Dually . This is the first time I've had the old girl up around 65-70mph since I first bought it. Since then, it's had a "new" 1,990 hr injection pump, 1.5 turns on the fuel screw, the tranny tightened up, and front end work.

She felt real good at 70mph, but was running out of steam after 75 or so. Not to mention I still havn't installed my EGT gauge (I know, I know), so I wasn't trying to gain speed pulling hills or anything for safety sake...

Anyway, I could run on flats no problem with my foot barely on the pedal. I could gain some speed and hear it spool up by pushing into it lightly. But when large hills came, I would have to REALLY push on the pedal, then all of a sudden there is a sweet spot where it will just TAKE OFF. Is this normal for a turned up pump? Will this disappear when I put the 3200rpm spring in? I don't like this non linear feel on highway speeds.

 

Timing will fix all your issues.

we Had 2 non i/c 727 trucks been there done that. 3200 spring will make a huge difference + 1/8 timing bump.

 

Thanks, I purposefully set the new pump at stock settings in case it was slightly different than the stock one, which it wasn't. I was going to set the timing up for my trip back to see how mileage improved, but my buddy didn't have a bent wrench for the last nut. Oh well, I had 21.5mpg on the way down and about 18.0 mpg on the way back due to going into the hilly section of CT and running a little faster and aggressive due to traffic.

 

The 366 spring will give you A LOT more steam around 70-75. You won't have to mash it anywhere near the floor.