I looked for the same a few years ago and there is very little about. although there are quite a few photos of the racing MK2s that are on the current classic racing circuit. Most racing Zs seem to have either tripple SU carburettors or triple Webbers. The Ford works MK3 Zodiac program only lasted for the first year or so before efforts were shifted to the Cortinas and Anglias. Graham Robsons book "Consul, Zephyr Zodiac" has pictures of the cars but not under the bonnet (as they were "production" cars I would imagine they would have been pretty standard as far as looks were concerned. There are some videos on YouTube (British Pathe) showing early saloon car racing and some shots of Zephyrs.