Rocker Arm Ratio

I have a chance to purchase a set of roller rockers with shafts.
The only problem is the seller bought them from someone else
a while ago and is not sure of the ratio. Both look like they are
new. How can I determine whether they are 1.5 or 1.6 ratio?
There is nothing stamped on the rocker arms.Thanks for your
help. I appreciate it.
Author: admin