Im looking at buying this truck,, what are any inherit problems with this model?

 

Reputation for bad injection pumps.

 

Is it a 12 Valve or a 24 Valve?

 

If it actually is a 98.5 as he has listed - it would be a 24 valve
98 = 12 valve

 

Would it be likely that this pump has been replaced with 160k on clock? What would be the signs of failure?

 

Look for some knuckle skin on some of the sharp edges near the injector pump.Maybe a little bit of blood too.

 

53 block

 

YES the 98.5 I don't think it would have the same pump most if not all the early pumps were bad and seized up or fried but then again most vp 44 die one way or the other
and look for the 53 block

 

there could be a "53" stanped on either side of the block right above the oil pan right behind/below the oil cooler on the passenger side, or in front of the ECM (block mounted computer) on the drivers side. these blocks are prone to cracking due to a casting flaw. however not all 53 blocks have the casting flaw. as some 53s were cast in Brazil (bad ones) and some were cast in Mexico (good ones) one way to tell if its a brazil 53 is look on the bototm side of the head on the intake plenum towards the back it will say brazil. if it was made in mexico it will not have a casting. also be aware to check for a crack in the block it happens on the passenger side under the exhaust manifold and is typically appearant... unless you get one like i had and the PO jb welded the entire side of the block and spray painted it so it was undetectable. Ask if he has recently replaced the lift pump or injector pump. check it for codes. if you get a code p1693 that means there is a code stored in a different computer than the PCM. The ECM is usually what you dont want to see codes in. p0216 is vp44 death code. check the front end and steering rack make sure there is not too much slop in the steering wheel. the dashes like to crack. other than that with a little investment after you buy a dodge cummins you will have a great truck that will do way more than you could ask of it.

first off you should upgrade your lift pump to a frame mounted high volume pump... it will save your wallet in the end.
then if you have an auto throw a shift kit and a good upgraded torque converter. if you dont plan to make 500 hp the hughes 15lxfm performance is a great economical decision
if its manual I suggest that once the existing clutch goes out Valair makes another great economical choice for a clutch that can hold 550 hp and tow up to 10000 lbs no problem.

these things are not necisary but they will enhance the driveability and fuel mileage of your vehicle as well as put a big grin on your face.