Then reason for asking is that the # of SB heads out there gives you a lot of choices. Whether you want them for a 15mpg, 15 second street car or an 8 second dragster does come into play as to your choice. If your looking for non-CNC'ed heads, Dart is my favorite. They run well with very little port clean-up. The material, casting quality and machine quality are as good as it gets. For the price, there is no better. You can get them from 180cc to 230 cc depending on your combination needs. For CNC'ed heads, AFR edge them a little. You pay more for them. Canfields like all others will run and can be made to work OK, it just depends on you goals and combination to go with it, and how much you want to spend.