Ever here of the 1972 & 1973 low comp. 340? I owned a 1972 340 duster, best ET was 15.70. I also owned a 1974 360 Duster, best ET was a 15.30. I not sure about this but, I think the low comp. 340's HP was 240 & the 360's were 245 horse power. I had seen a 360 Duster in a 1974 Car Craft mag road test, it had ran 14.30's. There is no doubt the early 340's were giant killers, I think some of this was the optional gearing (3.91). The 360 a-bodys only had an optional 3.55 gear. When the 72-73 340's lost the big valves & comp. they lost some of their bite.