So I have a mid 70s 460 and I am noticing with my timing light my timing was out of place so I adjusted the HB to 0 degrees on compression stroke and distributor pointed to number 1 cylinder. I unplugged the vacuum advanced as I heard I was supposed to do for messing with timing and started the car, ran like booty at about 600 RPM and I checked timing. Before I readjusted, it ran okay with a slight roughness at about 1000 rpm without kicking the choke off but very very lean as with it running preadjustment the balancer showed as far above 0 degrees as the timing marks went. After Adjustment, the pointer was not on the timing marks anymore with ATC above the pointer. Does this mean my timing chain is bad and needs to be replaced? I am kinda assuming this already but I always want second thoughts on such important things as timing and a big job such as this. Please and thank you!