MK1 Engine Problems (Noob)

mk1 4age engine problems, fine, started, engine, noise, levels, hissing, white, smoke, made, today, miss, barely, firing, ordinary, driving, short, distance, drove, days, couple, problems, noob, restoring, perfectly, sudden, lost, power, drive, tick

I am restoring a mk1 and a couple of days ago i was driving it a short distance. it drove perfectly until i got to the top of my drive when all of a sudden it lost power, wouldnt tick over and the engine had white smoke and made a hissing noise. the oil levels are fine nothing seems out of the ordinary. i started it today, it started fine but barely ran and was miss firing. PLEASE HELP