99 was the first year for the F350 SuperDuty. The diesel has the turbo and an intercooler. The bad thing about the Power Stroke of that vintage is the CPS (camshaft position sensor) going out. Most people carry a spare in the glove bos and a 10mm socket to pull it when it fies. Anout a 10 minute job.
Next issue with the trucks is ball joints. They tend to go bad and it probably due to the weigh tof the diesel engine.
The F250 of that vintage has a GVWR of 8800# a nd the truck will weight about 7000 to 7200# if a 2 wheel drive. So that will leave you with a payload capacity of about 1600 to 1800 # for your pin capacity.
You can make the engine a bit quiter by installing a high pressure oil rail bypass kit. It lessens the "cackle" a bit and helps to smooth out the idle. HERE