Where do I connect one on a 2.8 V6 I know on the 305 there is a nut behind the distributor. I was wondering if there was an equivilant

 

Simply, the best place to put the mechanical gauge's oil line on the engine is to use the hole that either your oil sending unit or oil switch uses. Since you have a Berlinetta i'm not to sure which kind it use's but it is located right next to your oil filter, though I can not remember what size the taper threaded hole is at the moment.