273-2 had a helluva piston pin. So much as to make it the same weight as a poly 318's bobweight. 273-4 had a thinner wall pin to offset the taller pistons weight.
Agreed, they all used the same crank, including the 318 Poly till 67. All piston and pin combinations weighed the same and used the same rods during the time period. 68 and 69 273's used the same 318 cast crank.
