Here's the low-down on late 70s heads: Late 76, all 77-up, Ford went with a single head for all it's 302s and 351ws. It was thinner cast than ever, had more bumps and turns interfereing with the port shapes, and was smaller where it counts. The ONLY difference between 302 and 351 heads during this time was the size of the head bolt holes. So, overview: Smaller valves than ever. Smaller ports than ever. Small ports with thinner walls, so porting was only moderately effective, and only if you didn't make the metal too thin. Biggest combustion chambers ever. Small ports with more emissions plumbing goofing them up. SO, here is what is possible: Machine for 1.94/1.60 valves Mill head some for decreased chamber volume, but not too much, deck is thin. Domed pistons to bring the compression back the rest of the way. Port and polish, but not nearly as far as you can the earlier heads that not only started with larger and smoother ports, but also had more meat to port. More machine work to lose the pedestal mounts. Now you have sunk a bunch of money into the heads... Leaving the fact that aftermarket heads are available, totally out of the arguement, you spent more money on these then to have the same mods done on a set of 69-73 W heads, and have a lesser product. I say you spent more money because: W heads have a small enough chamber that you won't pay for milling or dome pistons. W heads should be cheaper to stud and plate. W heads have a much larger port and more meat, so porting will result in a better port without paper thin metal. W heads have the largest SBF valves, so the Chebbie parts aren't even needed if you don't want to spend the dough. If you go for a 71-73 W in a station wagon for example, you won't even pay more for the cores because no one would consider them a performance part. The 74-early 76 W heads are exactly the same as these, but they have some emissions plumbing to consider when porting. Dave
