I bought a couple sets of 440source heads years ago. They flowed slightly less than what Edelbrock heads did from what guys were claiming. They flowed a max of 267cfm on my bench. Quality was nice and valve job was ok for an out of the box head but pretty basic. A rather basic three angle valve job and some quick work cfm max numbers jumped to 300 and I quit and sold them. I hear they fixed the issue but the chamber was cast to big. The fire ring on the 1009 and 1039 was in the chamber and couldn’t be used. There offered a white head gasket for awhile that I guess addressed this but many guys used the marine head gasket. Of memory it was a Felpro 11059 or something like that. Just to add back then even Edelbrock said not to use the 1009 gasket for the same reason.
