318 cylinder head choices

I think in terms of ease of aquisition and potential a set of Enginequest Magnums might be the best choice. They have the best chamber, a well designed port, and will move plenty of air for a 318. I would pair it with the XE262 as the 268 might be too much with the 1.6 rockers. You can get a set of them ready to go for under $800. To properly go through a set of older ones will cost more in most areas, and the bigger 340/360 heads IMO will just lose you compression and not help too much in terms of detonation resistance.