Harley's M8 water cooled heads engine would be a good choice IMHO. Harley is offering this engine as a crate engine (so Morgan should have no problems buying them) and it is expected to be Euro5 compliant. Harley needs money, so I'd expect they'd be keen to offer up engines with fuel delivery system with EPA/EU5 certificates. The M3W cowl has room for a radiator behind the engine, this would look correct and pay homage to the early M3W with water cooled J.A.P. engines. This would allow Morgan to continue offering the Three wheeler with minimal development cost (compared to an all new design).
Perhaps Morgan has a B-Type in the works?
CX Chassis & BMW drive train (as current Morgans). Engine B38B15M0 turbocharged 1.5l inline 3 cylinder engine (100Kw -134hp & 220Nm -162 ft.lbs), Euro-5 & US EPA compliant. Longitudinally mounted (as in BMW F20) powering the rear wheel and attached to BMW manual (or auto dual clutch 7-Sp with paddle shift). Or perhaps even in a front wheel drive layout (as Vanderhall) with the 1.5l & transaxle from the Mini/FWD BMW.
I'm not a big fan of Harley, but would prefer a V-Twin out front M3W over any other options. As far as I can tell, Harley is the only V-Twin motor with a separate gearbox, expected EU5 emission compliance, and available separately as a crate engine.
