Engine

I saw on Craigslist a rebuilt 429 engine, and considering the short amount of time I have to get this car done, and my suspicion that my engine is not running right and needs to be rebuilt, I thought, maybe I'll just swap it out for one that runs right to begin with. But the 429 that's for sale is from a '64 and it won't bolt into my '67 without a new tranny (which I may need anyway). I think I'd rather get a engine from a '67 anyway even if I were to swap it out. Oh well.