Tough question. Bobby Czyz was a bulldozer. A very strong and durable fighter who had skill but often fought with heart and toughness instead. Carl Froch was equally tough and talented. Czyz was a bit bigger and fought at the slightly higher weight which might be an advantage but probably not a huge one. He also had the tendency to cut and bleed quite a bit. This is very close. I’m inclined to taking Froch by a razor thin decision but I can’t say this with any real confidence or conviction.
I pick Froch by late TKO. Bobby Czyz was tough when he had mediocre guys but he lost to the top guys at light heavyweight Virgil Hill, Charles Williams and Dennis Andries. All three beat him. I think Froch would stop him on TKO.