on my 1996 1HDFT/h151 80 series... one small thing I added that made a huge improvement... I soundproofed the heck out of the center console/shifter console. The H151 has a rather noise transmission, and the 1HDT isn't exactly quiet... the difference was night and day.
I skimmed the write up here... but did you replace the bottom end bearings (connecting rod bearings). On every 1HDFT, 1HDT, 1HZ i've worked on, I replaced the bearings and they were all in bad shape. It's cheap insurance. The other thing is the valve adjustment... which is a royal PITA, but necessary. Also, the fuel pickup (the tube inside the tank) has a factory "screen" on it. Mine was covered in algae... I deleted mine and run a second filter instead (easier to change/clean). Lastly, the factory fuel filter has a "water in fuel" sensor. Double check that yours works... mine was not hooked up, and a bad tank of fuel in mexico blew out my recently rebuilt injector tips. 99% of the time, diesel fuel is fine... even in Mexico... but every once in a while you'll get some water and if it makes it to the injectors bad things happen.
sweet truck.