Tractor Repair: highspeed diesel miss, allis chalmers, glass filter

Question
i just bought an allis chalmers 7060, with the 426ci, turboed intercooled, 6cyl diesel. it's a 1975, but think this is a general question. the guy i bought it from had run it out of fuel. he got it going, runs pretty good up to 1500rpm, them gets rougher. i've put in all new fuel lines[including between the 2 tanks] also a new 12v booster pump and glass filter. have bleed both the pump and injectors several times. is there anything else before i start looking at the pump and injectors? is there a simple way to tell if it is a pump or injector problem? any help will be greatly appreciatted. thankyou, loren

Answer
Crack the injector when your engine is running see if any cylinder sounds different when cracked open that would isolate what injector is bad. If they all sound the same then you need to look at your pump. My advise after your tests take out all the injectors and have them tested. If the all check out then you know its the pump.Most dealerships will test your injectors for free.