Some of the Vintage trucks I used to rebuild a long long time ago suffered from a Knackered Diesel Pump which usually produced more black smoke than the Bismark trying to get away from a few cruisers, lol, so I think it's likely to be the same problem.
It could however be a poorly set up pump, or even the Diesel Equivalent of it, as it tends to be a massively over-rich partially burnt oil residue that's coming out of your exhaust.
As I say, it could be any manner of things like the timing way out or even the Fuel delivery system completely shot, so I'd wait until some of the Diesel Experts have a chance to diagnose your problem before taking any notice of my comments.
Having said that, the smoke can only be one thing, it's just the cause you're looking for.
A good Service wouldn't go amiss either.
Good Luck
Stew
It could however be a poorly set up pump, or even the Diesel Equivalent of it, as it tends to be a massively over-rich partially burnt oil residue that's coming out of your exhaust.
As I say, it could be any manner of things like the timing way out or even the Fuel delivery system completely shot, so I'd wait until some of the Diesel Experts have a chance to diagnose your problem before taking any notice of my comments.
Having said that, the smoke can only be one thing, it's just the cause you're looking for.
A good Service wouldn't go amiss either.
Good Luck
Stew