The ratio to convert 6.5 pounds to ounces is:

$$1 \text{ lb} = 16 \text{ oz}$$

So, 6.5 pounds is equal to:

$$6.5 \text{ lb} \times 16 \text{ oz/lb} = 104 \text{ oz}$$

Therefore, the ratio to convert 6.5 pounds to ounces is 16 ounces per pound.