The info I have, for the original 1100 D46
The engine was FIAT based 1100 cc (1089) 4 cyl in line overhead valves. Bore x stroke 68 X 75 mm.
60 bhp @ 5500 rpm.
On the photos I have on file, 2 single choke Solex downdraught carburettors.
The 2000 cc BPM Marine based engine had 4 DelOrto carburettors