Hi, I am swapping out a sweep style dash in my 71 Elcamino for an ss tach and guages dash. If I get an ss tach and guages dash from a 72 chevelle or monte carlo, will I have any trouble hooking up the 72 dash wiring harness to my 71 el camino?

You need the wiring harness to match the round gauge dash... chevelle or monte will work (you need a 72 so you have the seat belt warning wiring). If you do a search, there should be alot of info on the swap