After looking at the pictures again, it looks like the exhaust valve spring is a larger diameter than the intake spring. Are you sure the springs are a matched set? Just a thought.
Left spring sure does look bigger and so does the retainer. Matter of fact, both retainers do not look centered, maybe the angle of the picture.
Did you buy these heads from edelbrock or private party?
I believe its time to get out the dial calipers and start checking diameters of springs and retainers.
If you bought these heads from a private party and springs and retainers turn out not to be a matched set, I would buy a new set of beehive springs and retainers. Much better springs and you will have all the rocker arm clearance you need.
