RE: Sig Kougar Build
The measurement is from the LE at the tip - sorry about that.
Don't recognise that mount. The orignal sig mount was a 3" 2-piece aluminum thing - now is changed to glass filled nylon, I imagine because lots of people broke taps off in the aluminum...
The present one is pretty rigid and would stand having an engine far out on the mount to get it far enough away from the firewall for the cowl