Good info, Bart- - - -also, the "camel hump" heads that people talk about actually represent 5 or 6 different casting numbers with at least two slightly different CC volumes, 1.94" and 2.02" intake valve sizes, and a variety of accessory bolt holes on the ends, or no holes at all on the early ones. There was also a 64 CC angled spark plug variety with no heat riser passages known as an "off-road" head that was only available as an over-the-counter purchase from a Chevy parts department. We used a LOT of them on 600+ HP round track engines in the late 1970's.
Jerry
