I didn't use it because the B & C spline driven alternator I used fit without it.
I did contemplate using the bigger alternator they sell that requires it, so I did a cursory check and felt it would fit, but I might have to fiddle with some hoses.
After installing my engine I can now see that there are several hoses from the firewall forward kit that might need to be changed out and or rerouted. They include the oil vent hose, and the oil cooler. I believe they will interfere with the hoses and clocking of the fittings in the firewall forward kit.
I believe rerouting with different sized hoses will work. The oil vent line should be easy and could be done with the materials in the kit I think. The oil line to the cooler looks more complicated. Probably need a different hose and routing.
It appears that the oil filter itself will clear the mount and the cowling.