does anybody know what manufacturer the following engine-number (taken from v5c) might indicate: UMO3951

'um' might be 'unimog' a german supplier.
a photo of the engine might make it easy.

its a british kitcar....

Ford used the engine code UM

Engines manufactured during July 1978.

Linky to Burton Power

http://www.burtonpower.com/tuning-guides/tuning-guide-pages/ford-manufacture-dates.html