The Chevy Power Manual has pictures of these lifters. The standard solid lifter was the "piddle valve" and it has a hole for oil feed in the machined down waist area (typical of the hydraulic and sold flat tappet lifters you see today). The "Edge Orifice" reduced oil feed solid lifters have the oil feed hole on the large diameter of the lifter body so it gets a lot less oil feed.
The Power Manual also shows the "Mushroom" solid lifter which has a larger foot that rides on the lobe and must be installed in the block from the bottom of the lifter bore. The mushroom lifter can move the valve faster due to the larger foot at the cam. More agressive cam profiles are possible.