Sorry about that. I was going by Edelbrock's website that shows 60619 as a bare single head.
Edelbrock.com - Cylinder Heads - Chevy - Small Block - Performer RPM Small-Block Chevy
I should have known better because my pn 6073 heads have 6061 cast into them also. As I said earlier they are straight plugs heads, but 70cc.
I believe you'll find the actual part number on the end of the head where the accessory mounting holes are located. If they are that old they probably have the flat tappet cam springs installed.
Some here have said that you shouldn't try to do any porting on them, and that they are optimised from the factory.
I don't agree, and believe they can be improved with a little time and effort.
Again sorry about saying they were angle plugged. Just trying to help.