I can't see a label on te cells in your pictures. Without a full model number, we don't know the ratings for the cell discharge current. Many LiFePo4 cells can put out some serious current, but other will over heat. Since we have no idea, I would not go more than 2C or about 40 amps for the pack as is. If it runs dead cold, maybe you can push it a bit more. Maybe do some testing before you spend money. If you can take it further apart and find a label on the cells, maybe we can find more data. I did a few searches on Sony LiFePo4 cells, and did not find any that looked right.