During the course of development testing one of the AEC’s current production engines was used for comparison - the ‘datum engine’ The results were interesting.
“In the development stage, the stroke of a modified 180 bhp datum six-cylinder engine with the same bore as the proposed V8 was reduced to 4.5in. to match the V8’s stroke, and the unit produced more power and a higher torque than the standard engine. It also operated at a lower fuel consumption, corresponding to the consumption of the 800 series V8 of 0.369 lb/bhp /hr.”
Read more at archive.commercialmotor.com/arti … dAizr8w.99
As mentioned elsewhere in the article, the V8 was intended to be used initially ahead of a six speed gearbox. At the time (late 1960s) there was by coincidence an American engine that had made an appearance in the UK which perchance had an almost identical displacement: 743 cu in against the 741 cu in of the AEC V8 and almost identical bore size. (5.1" 130mm) This engine was at that time very frequently mated with a six speed transmission. This engine was less powerful than the AEC, but its rated output was at 2100 rpm and its peak torque occurred at 1550 rpm where it produced 600 lbft … very similar to the AEC V8’s (580lbft) which was however at a slightly lower speed (1400rpm)
Now all this may be pedantic technical mumbo jumbo, but from a driver’s aspect if stuck with only five or six available gears, then an engine which has a 1200rpm spread of useful torque and power is less tiring to drive and more appealing than one which only has 550 rpm available.
However one engine had two more cylinders so maybe we shouldn’t compare the two.