Hey thanks Steve, perhaps due to that the box is located in a different area. That could easily cause the harness location difference thereby causing the poor fit.

Prior to your mention of the steering column coming through the cab at a different angle, I had assumed that it was because the frame might be Narrower on the D300 vesus the the 100 or D200. {Still wondering)

It was only about 1/4 inch where it contacted the 318 engine block and I figured I could hopefully grind that much off the block where it made contact.