heads for 318

That sounds like a fairly potent combination you have there right now. Any time you can get a 318 into the 12's with a fairly mild combo like that, you're definitely doing something right. The heads you have there now obviously have the right size valves and ports to give good flow velocity with your engine combo. I doubt that a switch to Eddies or mags will give you enough of a gain to justify the cost. Having been on the "younger women, faster horses, older whiskey, and more money" wagon since I was a young feller, I know where you're headed, but how fast do you want to go with this combo? Remember, you're better off with a good running, RELIABLE, combo like you have there, than with a finicky, fix-it-weekly machine that will run a 1/2 sec. faster in the quarter mile. :)