first of all i am new here. i am a civilian contractor for the army and work on all kinds of militaty vehicles but have never messed with an LDT 465-1C motor. My neighbor has a 1971 model M51A2 5 ton with a 1975 white LDT 465-1C motor in it......i am not even sure if they put these motors in this truck but he says the guy he got it from swapped out the motor. He can not get the thing to run and wants me to fix it for him. It is getting fuel up to the injector pump but nothing after that. He said the piston in the injector pump head was froze up so he dumped some kind of solvent down it and got it freed up. He has another used injector pump he got for it but i am just wondering if i should try and swap the ip heads out first and see what happens or go ahead and just change out the whole pump? any help is greatly appreciated