i'm having trouble finding a site that gives hp ratings specifically for the A14, but have found a couple with A-series specifications. i think they were rated at around 70 hp, but that rating is an exaggeration. the stock L-16 datsun engine (in a 510) was rated at 96 hp, but made closer to 65-70 hp.
a datsun 1200 website
http://martybugs.net/DatsunMods/engine.cgi
wikipedia on datsun A-series motors
http://en.wikipedia.org/wiki/Nissan_A_engine