So, to make a long story long, back when I thought I was going to restore my grandfather's wagon, the rear bumper was completely rusted out.  I actually had to cut it off, and even before I did that I knew I needed a new bumper.  I bought an aluminum one from a 79/80.  It will fit my car (both are 76's), but I need to cut the plastic bumper filler piece.  I don't mind doing this as I have an extra one from my grandfather's car, but it is not as sturdy as the steel and chrome one from the '76.  I like the look better and the fact that it weighs less, altho the front will stay the same.  Is it safe to use the lightweight aluminum bumpers, or should I go back with the original 76?  I'm not worried about it being completely stock, more so on safety and that they are lighter and may also shift more weight up front.

you could have used the 77-78 bumpers, they weight the same as the 79-80 bumpers, but look like the 74 to 76 steel bumpers , bet you save over a 100 lbs by doing that , but change both , using the 77 bumpers on my 79 cruse wagon along with the 76 front end and grill , the 79-80 bumpers are strong , tested them when I lived in New Orleans years ago , lost a few pintos from all the bad drivers there