The Kent name was used to cover a whole range of pushrod OHV Ford engines that came along in 1959, and were made in 1000, 1200, 1300, 1340, 1500, 1600 sizes that I can remember, and maybe more!
The first versions were 3-bearing for the Anglia and Classic, then the 5-bearing engine came along and finally the crossflow.
Lotus engines were built on an overbored pre-crossflow 1500, and the water pump arrangement was part of the original design.
The engine was specifically designed for the Elan, and I don't believe any Elans had any other engine fitted. I also believe that there were very few 1500 Lotus TCs and they never got into production cars.