Personally, I feel Morgan chose the gearing really well, and I'm not sure I follow your theoretical top speed argument to suggest lower gearing would be an improvement?
Fifth is an overdrive gear, the ratio was not chosen with the intention of hitting 165mph at 6,600rpm, Morgan chose the ratio wisely so you can cruise at 77mph with the engine only turning at a relaxed 3,000rpm. Actually the car would pull a
theoretical 184.48 mph if the engine could reach its red line of 7,200rpm, but obviously aerodynamics take over long before that.
Clearly the gearing wasn't chosen for the theoretical top speed, the overdrive ratio of 0.73 was 100% chosen for fuel economy and modern motorway cruising refinement
Mogan then used a five speed box so you can enjoy maximum acceleration in the lower gears, but also benefit from that relaxed cruising. According to my owners manual, Morgan equipped Monty with a 3.73 diff, if lower gearing really was the way to go you’d think they'd surely have chosen a shorter diff for their more performance focused Super Sports model?
But they didn't, the Super Sports retained the 3.73 axle ratio, I suspect this was because customers wouldn't have been very happy buzzing along the motorway at over 4,000rpm in 5th. However, what Morgan did do with the Super Sports was increase the engine’s power output by 30%, this was the smarter approach as it significantly improved acceleration using the same gearing as a standard Plus 4 but also meant the car retained its ability to cover ground at motorway speeds without the engine revving its nuts off.
I’m also in no doubt that selecting a lower diff ratio would make 1st gear completely useless, all you’d end up with is a noisy unrefined car at motorway speeds that in all usable respects also had a for speed gearbox, basically a return to the bad old days before five speed transmissions become commonplace.
The lower ratios are also well chosen, for example let's say you're looking to achieve the maximum 0-60 time. Just put the car in 1st gear and wind the engine out to 6,400rpm, at this point you'll be travelling at 32mph, now change up to 2nd and by the time the engine is at 6,400rpm again you're doing 60mph, and like this you've only had to change gear once.
For all these reasons I won't be changing the gearing in Monty, I’ll be increasing the engine’s horsepower and torque outputs instead, just as Morgan wisely did when they created the Super Sports
