That's heavy! I have a Record No.8 vice. It has 8"jaws. I'm pointing that out because for Records, the No.__ doesn't always indicate the width of the jaw. For comparison it weighs 85 lbs. It's a monster and to be honest a pain in the butt to use because of its height. I'd have to put it on a lower bench to use it comfortably and that would make using the bench uncomfortable.
Have you tried Acklands-Grainger (which I think is just Grainger in the US)? They have a good range of hard & most soft jaws for Records and they're not that expensive (about $45 CDN with screws).I have a 4" Columbian from my Grampa. Needs new jaws...I'm going to have to make them. Haven't been able to find anything to buy.
I'd really like to find a 6" somewhere. Something older and at a garage sale...so its inexpensive!