I have been looking all over for a replacemnt CTO (ported vacuum switch) for my 87 YJ 4.2L carbed jeep? Amazon and others has one they say fits but it only has 3 nipples/ ports. There is not an original design to be found. I now have a 5 port with one plugged so I'm using 4. The front left and back right are Y'ed together for ported vac so I figure those could use one which puts me down to the 3 needed. OK so far? On the new type what nipple goes to what line? Rear to canister purge, middle to ported vacuum and front to EGR? (The base at each nipple steps down in size going out for what that's worth). Will this give the ported line enough vacuum now that it's down to a single port? Got a new EGR coming and wanting to salvage the emission system for authenticity.