Engine replacement

[bigboyisme]

Recently I had a problem with my egr hose blowing/burning off the exhaust hose. Now I know that it is a clogged converter, but since then the vehicle has what sounds like a rather severe rod knock. Would there be anything else causing a knock like that, that would have to do with the exhaust system?
I am contemplating having the engine replaced in the next week or two, but I want to make absolutely certain there isn't anything else that may be causing the problem.
While I'm at it, does anyone know where I can get a decent used engine from a reputable place? I can't afford a reman'd engine at this time so that is outta the question. I have been quoted around $750.00 for engines through a bunch of used parts dealers, but I'm sceptical about the quality of used engine I would get. Any tips would be greatly appreciated, Thanks. Happy New Year