This can be done rather cheaply if you are patient. I picked up a 67 327 short block complete with forged 12.15:1 pistons and all the machine work was complete for $200. Originally he wanted 400, but after a week he came down as he needed the cash. this price included the complete gasket set, including head gaskets. 283 cranks can be bought on ebay very cheap, under $50 in some cases, they seem to appear in spurts, 2 or 3 at a time and then nothing for a few weeks. The pistons are getting scarce, but I managed to buy a new set of forged 302 .020" over from Smokey for $70. These prices are really low, but it shows you how cheaply you can get some of this stuff if you are dilligent and patient. I never had to ask anyone to reduce their price or offer them less than they were asking, I don't like to do that, in the case of the shortblock, the guy called me after a week and offered to drop the price. I stuck quite a bit more into the engine while putting it together, but again I'll bet I don't have $1200 into the motor, that's with stainless race flow valves, solid cam and lifters, Arp pro series rod bolts and many other good pieces. Of course I do all my own assemble and much of my own machine and head work. At that price I'll run it to 8500 all day long and if it doesn't hold up, I'm not out anything.
Don't use the 283 rods they are weaker than the 67 327 rods as can be seen by looking at the large ends. You probably should consider a set of Eagle rods for the small journal as a necessary modification.