goin' V8

I'd go for a 360 if I were you. I went through the original 273, then a 318 and finally put a 360 in my 66. I wouldn't ever go back to one of the smaller engines. Take your time and look around, don't be in a rush to grab the first thing that comes along. You're in calgary aren't you? You should have plenty to choose from in a 360 in that area.
What year / make / model is your car? The pre 67 models required fairly specific exhaust manifolds for the V8's. If it's 67 or later then you won't have any problems in that area.