i have been into a lot of GMC engines but I have never seen anything like it. i have butchered fire apparatus to build truck tractors, but they all had a power tower behind the transmission. I think this is something proprietary for the fire apparatus builder. I have seen crank failures with a bad vibration damper. And I have never seen an engine without one. What happened with your catastrophic failure? I would be afraid to run a setup like this because I have seen crank failures caused by a bad vibration damper. Front mounted pumps were common in the 40's and early 1950's. I would see what other fire apparatus manufactures used. The fire trucks that I cut were V-8 and had a power tower. If I was building a truck tractor out of something like this, I would put a vibration damper on it. It will be interesting to discover if this was the accepted coupling back in the day.
