HP - when was it used and why?

cudamark said

Really? I've had at least a dozen sets of the heads over the years and didn't see any HP stamped into them. Where exactly were yours stamped? On a machined surface or just into the rough casting?

Click to expand...

they are on the "915" big block 1967 440 HP heads with the larger 1.74 exhaust valves, most 915 heads had the smaller 1.60 valve but the hi perf GTX ect had the better 915 big valve head, they were usually stamped on the ends like the alt mounting hole area.