8BA & 8RT engines in LP Bren Gun Carriers

[ajmac]

There isn't a lot of point really.

Get a wartime 81 or a 59AB, these are the wartime 239ci and the postwar 239ci, externally they look identical, centre water outlet, same water pump castings, same bell housing and cam mounted distributor, the 59AB has an slightly higher CR and modified block casting internals for improved cooling, but only a little I think.
An 8BA did have improved cooling passages and modern rod bearings, but most of the redesign was a cost down rather than improvement. If you use one, you can get an adaptor plate to use the wartime gearbox, you will need wartime water pumps as the pump casting is different on the 8BA putting the engine mounts in the wrong place. You would need pre 8BA heads (24 stud) and an earlier front cover to use the original wartime distributor, which would mean changing the cam as I think the nose I'd different...in the end you would only be using the short block.
The 'best' engine would be a French 1990s flathead with pre 8BA everything else. When I say short block I include the valve train, 8BA valve gear is much better than pre 8BA as far as fitting and service goes.
All flathead distributors are terrible compared to the last of the line of distributors before full management came in, so having the side mounted unit would not be any better than the front unit, best would be to replace with a later chev or something that has both centrifugal advance and vacuum advance for better combustion at part load.