Frame Differences between 67-72 and 73-89 K10s

[67see10]

What are the differences between the 67-72 and 73-89 k-series frames.

The reason why I ask is because I have a 72 K-series truck that I want to swap dMax in. While doing some research, I ran across a company, Precision Fabrication Plus, who offers dMax swap products (swap mounts, engine and trans crossmember) for the c/k-series 73-89 trucks.

They claim that their products product two Engine Placement Positions, No Body Lift Required, No Engine Oil Pan Modifications, For use with OEM or Aftermarket Turbo, & Can Fit Up To a 3" Diameter Down Pipe.