How to fix my Kombi

I am looking for a advice on a cost effective way to fix my 74 Westfalia camper. It has a 1500 engine and will still run but pumps smoke out the outlet by the oil filler. NRMA said there was back pressure in the engine and it has dropped a cylinder. I am wondering whether to get a new engine, get a rebuild or even possibly having a go at it myself (although I don't have a garage and have basic mechanical knowledge). If anyone has a cheap second hand engine I could buy, please let me know. Other than that if anyone has any ideas on the best way to approach this problem please let me know.

there was a 2 litre engine for sale on here a couple of weeks ago for 150 bucks.
not only would you then get a (hopefully) non smoky engine, but the added power of a 2 litre.
getting a rebuild can run into $$$
keep your eye out for a good 2nd hand eng.
or for a cheap kombi or beetle with a good engine.
it is often the case that you can pick up a complete car for less than what you will pay for the engine alone.