Thank you so very much for trying to help me out on this.
Long-distance communicating and solving of problems like this is difficult, at best.
Regrettably, I am unable to get your most recent set of measurements to correspond to the bulkhead I have on hand
Center to center for the shoulder harness bolts is 48.125 inches. You gave the two center to edge of bulkhead opening dimensions as 16.125" and 9.25", a total of 25.375". That would mean the opening is 22.75" but my removable steel cover is 19.5".
I ....think.... The "bulkhead opening" you are referring to is the opening on your flat firewall. What I need, from the centers, is the distance to the edge of the metal engine cover. We need an installed kit to determine this measurement, I believe.
Very confused but still trying to figure this out.