Jaguar S-Type & 420
1963–1968 · a Mark 2 with independent rear suspension · and the 420 is not a Mark 2 with four headlamps
Three cars get confused here constantly. This page is two of them; the third is the Mark X.
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About the Jaguar S-Type & 420
The S-Type is a major redevelopment of the Mark 2, using the Mark 2 unitary shell with structural alterations to take a mid-scale version of the Mark X independent rear suspension in place of the Mark 2’s live axle — double wishbones with the driveshaft as the upper link. That is the headline difference and it changes every rear suspension, axle and rear brake part on the car. The front suspension is the Mark 2’s, retained. Brakes started as the Mark 2’s Dunlop system unchanged, despite the car being 152kg heavier, and moved to Girling calipers during production — published Girling chassis numbers are 3.4: 1B9191 and 1B26307; 3.8: 1B59653 and 1B80376. Engines are 3.4 and 3.8 only — there is no 4.2 S-Type. Body: extended rear bodywork and a bigger boot, a flattened extended rear roofline, reshaped rear wings sitting lower over the wheels, a larger more upright rear window and slimline bumpers with wrap-around indicators. Those rear screen and rear-wing seals are S-Type parts, not Mark 2 parts.
The 420 of October 1966 is an S-Type with a new square four-headlamp nose and a 4.2 engine. It is not a Mark 2 with four headlamps, and nothing at the back of a 420 fits a Mark 2. Its changes from the S-Type are genuinely useful to know: the engine is 4,235cc with twin SU HD8, not the Mark X’s triple carburettors, with a straight-port head and 3/8-inch lift cams for 245bhp; the electrics go to a negative-earth system with an alternator replacing the S-Type’s dynamo, plus a pre-engaged starter; the brakes gain a dual-line hydraulic circuit where the S-Type was single-line; and the radiator becomes cross-flow. The Daimler Sovereign of 1966–69 is mechanically a 420 — fluted grille, fluted rear plinth, flying-D mascot, better leather and walnut, and Varamatic power steering standard rather than optional.
Jaguar S-Type & 420 — specification & changes within the model
- The three-car disambiguation
- Mark 2 — compact, live axle, curved boot. S-Type — Mark 2 nose, independent rear suspension, long squared boot, 3.4 and 3.8 only. 420 — S-Type body, flat four-lamp nose, 4.2 twin SU. Mark X / 420G — neither; the 76.3in-wide flagship, and one car under two names.
- Brakes
- S-Type: Dunlop, unchanged from the Mark 2, then Girling during production. Published Girling chassis numbers — 3.4: 1B9191, 1B26307 · 3.8: 1B59653, 1B80376. 420: dual-line hydraulic circuit where the S-Type was single-line, servo discs all round, inboard at the rear.
- Rear suspension — the difference from the Mark 2
- A mid-scale version of the Mark X independent rear suspension, double wishbones with the driveshaft as the upper link. The 420 adds radius arms and twin coil springs per side. Nothing at the back of either car fits a Mark 2.
- Engines
- S-Type: 3.4 (210bhp) and 3.8 (220bhp), twin SU HD6. There is no 4.2 S-Type. The 3.8 outsold the 3.4 three to two. 420: 4,235cc, twin SU HD8, straight-port head, 3/8in lift cams, 245bhp SAE gross — not the Mark X’s triple SU.
- The 420 electrical breakpoint
- Negative earth with an alternator, replacing the S-Type’s dynamo, plus a pre-engaged starter motor. This is one of only three Jaguar polarity changes any source will state.
- Body and glass, S-Type against Mark 2
- Extended rear bodywork and bigger boot · flattened, extended rear roofline · reshaped rear wings sitting lower over the wheels · a larger, more upright rear window · slimline bumpers with wrap-around indicators. All of them are seal and glass breakpoints.
- The Daimler Sovereign of 1966–69
- Mechanically a 420. Fluted grille with D badge, fluted rear number-plate plinth, flying-D mascot, upgraded leather and walnut, Varamatic power steering standard rather than optional, about a 6.5 per cent price premium. Careful: from October 1969 “Daimler Sovereign” means an XJ6 instead, and the two share nothing.
- Production
- S-Type 25,043 (1963–68), peaking at 9,741 in 1965. Jaguar 420 10,236. Daimler Sovereign 5,824.
- Not claimed
- The date of the S-Type Dunlop-to-Girling change — the chassis numbers are published, the date is not. Also rear track figures for either car, and earth polarity for the S-Type (a dynamo is documented; the polarity is not).