Ford ltl 9000 3406b motor questions/speedo prob

The ratio came off the tag on the axle housing. I'll have to ask previous owner if the gearing was ever changed. Been swamped with Christmas stuff for the kids. Tomorrow sleigh ride all aft. then various family gatherings all weekend. It was running 1900 to 2000 rpm at 65 to 70 miles per hr coming back from eau Claire on 29. Guess its possible tach is off a bit but doesn't seem to be. Running empty I still have the steel log rack and the prentice F90 loader on it plus pulling the pup trailer also its a double frame so it adds extra weight to carry. Cleaned the speedo sender and put a o ring on it to give little more clearance end was dirty,Havnt ohms tested it yet no time. It has only 2 previous owners it was originally a milk truck then converted to a log truck by the owner I got it from. It's a starter truck for me and figured that it being mechanical engine I could do most any work on it. Plus I got it for a good price with a 16 log pup trailer. at least I think I did.

 

Assuming the rear ends Havnt been changed what would cause it to pull that rpm ?? Truck doesn't smoke gets good fuel mileage pulls hard I think. Seems,to run good it runs around 1750 at 55 or little over 58 maybe in 13th gear. I don't think the rear end was changed from what tag said. Am I low on power or something is it working harder to run that rpm to get 65 out of it ??? I e mailed previous owner to see if rear ends ever been changed. Waiting for response. Installing a boost gauge,pyrometer gauge,and fuel pressure to get some readings and see how things are running. I thought it was a bit high myself ,but it is set up to run in the woods.

 

Yes I'm putting 13 in. I'm new to trucking but not wet behind the ears Hahahaha lol. I know I'm new but wow I'm a little hurt by that one hahahaha. I was born in the morn but not this morning. Hahaha. All joking aside if I can't even go thru the gears I'd have no right to be out there running. Imo. Truck shifts smooth and previous owner put new clutch in about 8k ago and I can run thru the gears. You want tricky shift try running my old 48 panhead rocker foot clutch with jocky shift and run the throttle with your free hand and steer with that same hand. That will test ya the first few times.

 

I can hear it go from 12 to 13 and the rpm come down some. Splitter works in all the top end gears. maybe I'm lacking some power and I'm having to step on it more to get 65 out of it if thats possible. Going to change fuel filters and lines get gauges on see how things are reading maybe I'm low on boost out the turbo it Is original I believe. 800 k on truck.

 

Ok think speedo is fixed installed a o ring on it to give little more clearance,and cleaned it off,also the wires were missing some insulation so put some liquid electric tape on them. What should boost read and where on pump should fuel pressure sender screw in ???