“Just noticing the recent questions about XSP engines, I bought an XSP
engine from [Jonathan] Peck, this looks to be relatively untouched and I have
yet to investigate the condition of the engine, but there are some
numbers stamped onto the cylinder head casting on the flat area next to
the thermostat housing, Maybe the XSP guys could tell me what they mean.
They are S556, AV 18 8 (crossed out) 19.4cc (could this be the volume of
the head chambers) TDC (no number)?” Feedback please
