Started out my career with a COE Freightliner with 903 V8. I believe that was the engine size. Had a compression release chain under the drivers door. That was tough trying to pull that and press the ignition button at the same time.
I know you mean, starter button.
I haven't seen a compression release since the old NH Cummins days, didn't know they were on 903s
We would hold the throttle wide open, lift the valves and put out more smoke than an old Associated Transport Brown.
Ryder had so many complaints, they were all disconnected.