When I changed out the valve cover gaskets on my K10, I found that the heads were different. Right side is a 74-76 76cc 350/400, and the left side was a 80-86 60cc 305! I called the previous owner (a friend of mine for 10 years),I tell him about the heads being different, and asked which head he had swaped out. He told me he swaped out the left side ( hmmmm..., I thought). So the right side is for that engine. I get the block # of it and check it at Mortec, turns out that I have a 350 in the old beast, not a 305 like I'd thought! I love nice little surprises like this!!