I think mine is the same 1.60-2.0 but it is aluminum so I am little more gentle with it when spinning it in. Yes the valves are single grove, stainless. Like I said when I get home this afternoon I have a set of steel 7* retainers I will measure with to see if I get anything different.
'75 Plymouth Duster
Phase I 451 906/590/2-660 10.75/126
Phase II 451 Stage VI/590/1050 9.82/135
Phase III 383 906/Victor-Pump gas 11.30/119
"For by grace you have been saved through faith. And this is not your own doing; it is the gift of God,"
| 
