I would recomend rebuilding an engine that you don't care about ( 4cyl from a junkyard would be good ). The reason is, for rare engines or engines considered obsolete, some internal parts may be hard to find, such as pistions, cranks and a couple other things, and I'm shure your engine falls in this catagory. If it runs good and dosn't smoke, just run it, especially if you are on a budget. Also your engine being a flathead, it is pretty much age old technology that unless you get into building Ford Flatty V8's, you will never have to deal with this unless you are working on an lawnmower. I'm 17 and I got a '51 Chevy Fleetline, with a 235 and Powerglide, it has 62,000 miles on it, dosen't smoke at all and runs great, I have no need to tear it down.