The power pack heads are ok so long as you're not trying to make a Monster killer motor. If you want something a little better, go find a set of what was known as fuelie heads( double hump heads) Came on early fuel injected vettes, FI engines most commonly found on 327 engines early /mid 60's. Yes the heads were on engines with carbs also. Two versions of this head were made, you want the earlier one with the smaller combustion chambers. One disadvantage of these heads is they do not have the mounting holes on the front of the heads for accs,( alt, p/s a/c) so you would have to find the brackets that mount them.
DON'T go looking for angle plug heads 202 intakes and all the fancy goodies for a 350, the reason being the smaller bore of the 283, the larger valves may contact the cylinder walls makeing a real mess of everythng .If you can find a cam that comes close to the specs on a 327/350 hp. engine stock from chevy, that will be a pretty good engine , had a couple set up like that many years ago, I have to look but I think I still have a copy of a hot rod Mag. that compared all the heads, will look for it and get back to you.
