Jeffrey 1983

I've been restoring a 1983 Hiace LH60RV Pop-top Campervan with a Trakka fit out. Have reconditioned Diesel Fuel Pump, Injectors and fitted a new muffler. The engine is 2.2 ltr and still blows a fair bit of black smoke under load and goes through about 1ltr of oil every 2 tanks of diesel. Eventually I want to replace the engine with something a bit less agricultural and wondering if anyone can advise me what options I have? any help is greatly appreciated.