MG's pre-war engines were small, operated with modest compression ratios, and had unfavorable bore to stroke ratios - but they had their advantages too. They came with overhead camshafts and they responded well to tuning. Superchargers provided a popular upgrade path.
The MG PA's generator is gear-driven off of the crankshaft. Belt driven generators first appeared on MG T-series sportscars.
Lucas distributor and twin S.U. HV2 (1" bore) carburetors operated via mechanical linkage, not a Bowden cable. Intake air filters weren't provided from the factory.
NOTE: Spare Lodge Type HN spark plugs mounted in a Bakelite holder. Note that the holder bears the trademarks of both MG and also KLG (i.e. a plug manufacturer).
Centralized (right hand side) lubrication system ports simplified routine maintenance. "A: rear brake cable. B: front brake cable. C: front spring, rear spring, steering box, steering column, brake cross shaft. Lubricate every 500 miles with gear oil."
No thermostat! (MG didn't start installing thermostats until after World War II.)
It seems pretty much everything that could be octagonal in shape, was.
The exhaust manifold is marked "Qual-Cast" and "87687B, MG 490-105". The engine block is marked "2068A 165P". Lucas electric starter.
Optional equipment water pump (marked "MG 348/109 BA"). If this weren't installed, water would still naturally flows through the cooling system due to convection.