How long is the pin? Standard .990 or chysler size? How much gap between small end of rod and pin bosses on each side? These are all gonna be factors in determining pin selection. Standard .180 sounds on the small side but if its a chrysler size and minimal gap is between the rod and pin boss it will work. If .990 and a big gap then you should put something bigger in there.
Thats the nice thing about a billet piston or a pin guided rod forging, you can take out alot of the gap and reduces the bending momment on the pin, enables you to run a small dia or thinner pin and still keep the same strength.
I would rather see you use a tool steel pin. A .180 tool steel is fine an a .200 is better. You never gave to much info about the motor. How much power will it make on its own. That has a factor as well.