AUTOMETER sportcomp Oil Guage quick questions.... 71' 350

Hey everyone. I installed an autometer oil guage, mechanical I believe. The one with the oil actually going through the little hose. Where exactly does it go, I saw an old port from when I had a stock dash, this unscrewed and looks like the same size threading on the new autometer, its right below my distributor on the driver side, looks to be leading into the oil.

Also the little hose that connects, can it be trimmed, does length matter? Also it doesnt have to go INTO , as in touch the oil does it? Hope that makes sence..... Thanks