Yes, very informative and most likely very true. So the 125 bhp achieved by the 3 1/2 Litre (I would say easily with good fuel and the right advance) should be good for 90+ mph in a Saloon (and DHC) and the claimed 100mph in the SS100. The XK120 with ca 160 bhp could easily top the claimed 120mph, I recall a standard XK120 in Finland in the 1950’s on our terrible roads was recorded to exceed 200km/h (125mph).
Once and if I get it all sorted out and get my “running in” completed on the MKV DHC I will take her to a dyno just out of curiosity AND to be able to adjust the AFR to something reasonable under load, so I will know I am not running lean at 100-120km/h
I did the same for both my E-types before driving through Europe as I would hate to blow a hole in a piston on the German Autobahn at 200km/h+! (125 mph+)
FWIW I never got to test how fast they would go. I sold the Series 1 4.2L 2+2 that showed (100% stock) 228 HP (DIN) at the dyno and the best I got was slightly above 220km/h (137 mph), but that was with three passengers and luggage back in 2002. That was with the O/D engaged just above 4.200 rpm and a 3.31 final drive.
Three years ago when we were coming back from Europe (via Denmark and Sweden) with my at the time 15 year old son, we hit 229km/h (142 mph) on the GPS near Celle in Germany in the evening when suddenly there was no traffic. The problem was that we were very soon at our exit from the Autobahn to our hotel.
That was with the 1972 Euro spec, 100% standard V12 OTS #1S20183 at the time still with it’s original OPUS ignition etc. Final drive 3.54. IIRC in 2015 the dyno showed 233.1 HP (DIN) @5.375 rpm on the second run (35 deg overall advance) and the factory stated 272 HP (DIN) @5.850 rpm so I was missing a few ponies, maybe they could be found with careful tuning. (376Nm @ 3.710 rpm)
(US Spec was officially 250 HP (DIN) @ 6.000 rpm.)
That’s an unrestored car and not-rebuilt engine in any way, with just a bit over 100.000kms on the dial. Top up of course, very noisy above 5.000rpm in top gear, but not as much engine noise IMO as with the XK engine.
The MKV / MKIV engine is fine IMO until 4.000rpm, but unlike with the V12 I don’t feel comfortable taking it higher. Maybe I should think about changing the final drive (diff) some day if the dyno numbers look good! It’s not my car’s original rear axle anyways, when I bought the car it had the rear axle and rear brakes from a Ford Fairlane or something and therefore the spare wheel well (and the fuel tank inside it! ) had been “reformed” with a sledge hammer!
It would be interesting to find out what had been done to that one MKIV DHC that allowed it to achieve the 140+ mph on the salt flat.
Ps. Also really good to know that if we want to take a Saloon to 150mph, we need about 500 HP!