Engine Quest is the manufacturer. They are a replacement head for the Magnum series small blocks. There were two versions. Magnum intake bolt pattern and LA intake bolt pattern. CH318A and CH318B are the numbers respectively. Cast with better ports than stock Magnum. However, recently, the castings on these changed and now they are actually worse than the factory Magnums. Idk what that is all about and only relaying what I have read and been told by people"in the know".
