"David O" wrote in message
news

. . . O-320 E-series engines were produced in both
narrow-deck (ND) and wide-deck (WD). O-320 E-series engines use
either ECI class 6 cylinders or class 4 cylinders depending on whether
the engine is ND or WD respectively. Some Cherokee 140's were
produced with E-series ND engines and some were produced with E-series
WD engines. The O-320 E3D in my Long EZ, for example, is a WD engine
from a Cherokee 140 and the cylinders would definitely not fit Drew's
ND engine.

How does one tell the difference?

Rich "The Emeraude has an ex-Cherokee 140 E3D" S.