I have one in a P47 inverted with OB glow.
The engine was is a SPAD before hand and was run over propped which lead to detonation, It destroyed the liner and piston.
I fitted an new liner and piston kit, Prior to the rebuild this engine had done a lot of time and never dead sticked or failed to start.
Now its always hard to start (only start it with the plane inverted) but once started its perfect. It still has very low compression after 2 liters. Its is slowly getting better with running.
When its hot she will start 1st time.
What would be the compression on one of these engines, My other TT and Mags have a lot of comp.