5622-xx are standard gaskets, they fit iron heads (and others I'm sure). The 5917-xx gaskets are listed by Cometic as "Designed to fits engines with 318A Engine Quest or Edelbrock aftermarket cylinder heads."
Best I can find, that change is slight differences in cooling passage locations. I've been meaning to call Cometic and confirm that info, or get the correct info at least. But there's some reason why they make and list a different one for those two heads, and it's not just for fun.
With the SMs being a direct edelbrock copy, I've been assuming they those differences. If not, that would be great, Summit has the gaskets I would use in that case, in stock....for now.
