You can also try kadee 252's
There were a couple runs of the E units with different coupling situations. Here is the info from the Kadee site for Life Like Proto-2000. It has nothing for Walther's Proto.
EMD E-7 A & B #26 pilot, 23 Ends
EMD E-8/9 A 33 or 453, OR a 143 in a 252 gearbox (metal on metal coupler warning)
EMD E-8/9 (New Production) 26 Pilot, 23 Ends, or 455 for close coupling.
It has been replaced by #455. I have seen them and they are what you need my local hobby shop had them in stock.
I have several Proto E7/8 locomotives which I need to change the couplers on. I understand the Kadee Swing Bracket coupler #453 is no longer produced. Is there a suitable replacement. I tried the Kadee website, but it wasn't working. Would any other company couplers work. Thank you