new engine?

ok heres the deal. right now i have no vehicle, but my mazda that doesnt run. it will run but runs like shit, smokes like a tire on fire, and has no power what so ever, I just drive it on and off a trailor for shows and thats it. I would like to drive it everyday. I had been comtemplating the 302 swap since I have an 87 lincoln continental in my parents yard. I could use that engine and tranny and put a carb on it, and do that, but I could care a less about the whole v8 thing. i just wanna be able to drive the damn thing. I saw where I could get a newly rebuilt b2000 engine for around 550.00. whihc would be the quickest and easiest way to go for the time being? I am still gonna do the v8 later down the road, but ive not got endless amounts of money right now, and i need a damn ride. my fiance and I have been working out of one damn vehicle for about a month no, and I need a ride quickly. what would be the best thing to? buy a rebuilt b2000 engine? or do the v8? i need thisdone qucikly, so keep that in mind. i need to be able to get this thing running in about a weekend.