building my heads

The 302 ports vary from 115-120 in factory castings, then when you open the port up to the 360 gasket and port the bowl you will be somewhere around 130-134 cc's, even at this size the 1.78 is the best, and really up to 140 cc's. Most 302 heads can't and wont be hogged out to this size, as this is done by welding and raising the port roof line, which go's beyond the scope of the home builder. A factory 340/360 head comes from the factory at 150 cc's or there abouts, but is too large for the 318. We have found that 130-136 cc's is best with a 1.78/1.60 valve sizes. This should put you in the 210-220 cfm range and over 300 HP to the tires, or be capable of it.