There are two 1/4" X 20 drilled and tapped bolt holes in the block, just below the cylinder heads on the older blocks. They were for a set of sheet metal looms that kept the wires off the exhaust after they came through a set of 4-wire looms at the back of the block behind the heads. The tricky part was keeping the wires for the front two cylinders for each side off the exhaust pipe where it attached to the ram's horn manifolds. I believe there might have been a single 2-wire guide attached to one of the oil pan bolts in that area.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!