All ferrites look the same, just the size and mix is different. Fair rite part# 2631801202 should be enough size to get one or two turns of the harness and allow the IDC connector to get through the middle of the toroid. I have this one in my machine. I was able to get 4 turns of the harness in it. The one catch was I had removed the molex/idc connector to do it since I had to repin it anyway.
If you wanted to go a bit overkill in size you can get part# 2631626202. The problem is now you will need to support the thing somehow without it weighing down the harness stressing out the connectors. Its heavy! However it offers the most suppression ohm resistance per turn of the wire harness.
Something else to keep in mind is incoming AC RFI/EMI. There is a power filter connected right on the incoming AC cord inside the bottom cab. Its a silver box, has a MOV on it located usually on the left wall. Often times i find that these units are worn/failing and do not filter the EMI/RFI coming on the mains AC cord as well as it did 30 years ago. I replaced my EMI/RFI filter on my Embryon as I noticed phantom popping/scoring when my small beer fridge would kick on/off. While it helped the phantom popping and scoring still happened on occasion.
EMI/RFI issues is a pain in the ass. Often times its a bad ground or failing component that fixes these issues. Ferrites help a great deal, and essentially compensate for a bad circuit design that isn't properly shielded.