---
title: Jaguar XKSS · HICONIUM
description: Jaguar converted unsold D-Types into a road car without taking out the competition hardware. Sixteen were completed before the Browns Lane fire stopped the run; the nine factory continuations came six decades later.
canonical_url: https://hiconium.dev/vehicles/jaguar/xkss
image: https://hiconium.dev/og/vehicle/jaguar/xkss.png
---

> HICONIUM · Index: https://hiconium.dev/llms.txt · Every page: append `.md` or send `Accept: text/markdown`.
> Path: [Home](https://hiconium.dev/) › [Vehicles](https://hiconium.dev/models) › [Jaguar](https://hiconium.dev/manufacturers/jaguar) › XKSS
> On this page: [The price and the proof](#the-price-and-the-proof) · [Model readouts](#model-readouts) · [Documented sales](#documented-sales) · [A road car made from redundant racers](#overview-heading) · [Technical specifications](#technical-specifications) · [Powertrain](#powertrain) · [Structure and running gear](#structure-and-running-gear) · [Road conversion and identity](#road-conversion-and-identity) · [XKSS register](#xkss-register) · [The people behind the car](#the-people-behind-the-car) · [Sir William Lyons](#sir-william-lyons) · [Malcolm Sayer](#malcolm-sayer) · [William Heynes](#william-heynes) · [Member instruments](#member-instruments)

![A British Racing Green Jaguar XKSS, front three-quarter view on a fresh green field with washed light](https://hiconium.dev/images/cars/jaguar-xkss/hero-wide-2560.jpg)

# XKSS

A D-Type for the road

Jaguar converted unsold D-Types into a road car without taking out the competition hardware. Sixteen were completed before the Browns Lane fire stopped the run; the nine factory continuations came six decades later.

1957 · 16 built · Coventry

## The price and the proof

Indicative road-car band $12M–$16M · 5 documented road sales · 5 recorded sales on file. Modeled values are not observed sales. Nothing here is investment advice.

Confidence: low. The band is anchored by the $13'205'000 public sale of XKSS 707 in 2023 and Gooding's $13'000'000 to $16'000'000 estimate for unsold XKSS 716 in 2017. Original cars trade too rarely for high confidence, and individual chassis history can overwhelm a model-level range.

Original 1957 cars only. Jaguar Classic continuations, later factory conversions and replicas sit outside the band.

Two verified original-car sales define this ledger: XKSS 704 in 2005 and XKSS 707 in 2023. It says nothing about intervening private trades.

| Record | Amount | What | Venue | Date |
| --- | --- | --- | --- | --- |
| Road record | $13'205'000 | XKSS 707 · original car | RM Sotheby's Monterey | 19 Aug 2023 |

Valuation method and source rules: [HICONIUM standards](https://hiconium.dev/standards). Observed auction results across the wider market: [Market terminal](https://hiconium.dev/market).

### Model readouts

5 documented anchors. model v1 · seed jaguar-xkss. Compound annual growth is modeled price CAGR; S&P 500 is a price index without dividends. Forecast quantiles are not investment advice.

| Window | This car* | S&P 500 | Gold |
| --- | --- | --- | --- |
| 1Y | +1571.3% | +18.8% | +21.9% |
| 5Y | +80.6% | +11.4% | +17.6% |
| 10Y | +46.7% | +13.3% | +11.8% |

| Series | Deepest drawdown | Window |
| --- | --- | --- |
| This car* | -97.9% | Aug 2023 → Feb 2025 · recovered Jul 2026 |
| S&P 500 | -50.8% | Oct 2007 → Mar 2009 · recovered Mar 2013 |
| Gold | -39.3% | Sep 2011 → Dec 2015 · recovered Jul 2020 |

| Horizon | P10 | P50 | P90 |
| --- | --- | --- | --- |
| +6M | $11'888'230 | $14'421'897 | $17'495'549 |
| +12M | $11'493'208 | $15'010'466 | $19'604'108 |
| +24M | $11'163'956 | $16'260'644 | $23'684'126 |

### Documented sales

5 recorded. Every public sale on this file, newest first. Amounts keep the recorded currency. Source links appear only when the catalog stores a public auction-lot URL.

| Date | Chassis / label | Class | House | Venue | Amount | Currency | Basis | Source |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 2025-02-06 | bonhams · Paris, The Grand Palais Historique · hammer | Road | bonhams | Paris, The Grand Palais Historique | €250'000 | EUR | hammer | [https://cars.bonhams.com/auction/30406/lot/119/1988-jaguar-lynx-xkss-42-litre-chassis-no-e50376-engine-no-7e1798-9/](https://cars.bonhams.com/auction/30406/lot/119/1988-jaguar-lynx-xkss-42-litre-chassis-no-e50376-engine-no-7e1798-9/) |
| 2023-08-19 | RM Sotheby's · Monterey, USA · incl. buyer's premium | Road | RM Sotheby's | Monterey, USA | $13'205'000 | USD | incl. buyer's premium | [https://rmsothebys.com/en/auctions/mo23/monterey/lots/r0172-1957-jaguar-xkss/1374708](https://rmsothebys.com/en/auctions/mo23/monterey/lots/r0172-1957-jaguar-xkss/1374708) |
| 2023-08-19 | RM Sotheby's · RM Sotheby's Monterey · incl. buyer's premium | Road | RM Sotheby's | RM Sotheby's Monterey | $13'205'000 | USD | incl. buyer's premium | [https://rmsothebys.com/auctions/mo23/lots/r0172-1957-jaguar-xkss/](https://rmsothebys.com/auctions/mo23/lots/r0172-1957-jaguar-xkss/) |
| 2020-09-06 | Bonhams · The Autoworld Autumn Sale, Brussels, Belgium · incl. buyer's premium | Road | Bonhams | The Autoworld Autumn Sale, Brussels, Belgium | €184'000 | EUR | incl. buyer's premium | [https://www.bonhams.com//auctions/26494/lot/38/?category=list&length=100000&page=1](https://www.bonhams.com//auctions/26494/lot/38/?category=list&length=100000&page=1) |
| 2005-08-21 | Gooding & Company · Gooding & Company Pebble Beach · incl. buyer's premium | Road | Gooding & Company | Gooding & Company Pebble Beach | $1'925'000 | USD | incl. buyer's premium | [https://www.goodingco.com/lot/1957-jaguar-xk-ss-roadster/](https://www.goodingco.com/lot/1957-jaguar-xk-ss-roadster/) |

Prices are nominal USD results including buyer's premium. No currency conversion has been applied.

## A road car made from redundant racers

Jaguar withdrew its works team from international racing for 1957 with D-Type chassis still at Browns Lane. On 14 January, Sir William Lyons approved a plan to convert 25 into road-going cars aimed chiefly at North America.

The work was direct. Jaguar fitted a full-width windscreen, a passenger door, side screens, bumpers and a folding hood. It removed the D-Type's cockpit divider and stabilising fin; the monocoque, live rear axle, disc brakes and competition-derived straight-six remained.

The factory fire of 12 February 1957 destroyed nine unfinished cars. Jaguar counts 16 original XKSS roadsters; auction records also distinguish two customer D-Types later converted by the factory while retaining their XKD identities. Jaguar Classic began a separate run of nine continuation cars in 2017 to use the lost chassis numbers.

| Highlight | Detail |
| --- | --- |
| The competition car stayed underneath | Jaguar retained the D-Type monocoque, 3.4-litre six, four-speed gearbox and disc brakes. The conversion added weather equipment and a passenger door, then removed the cockpit divider and tail fin. |
| The fire fixed the number | Sir William Lyons approved 25 conversions on 14 January 1957. The Browns Lane fire on 12 February destroyed nine unfinished cars, leaving 16 completed XKSS roadsters. |
| Two production sets, one shape | Jaguar Classic built nine continuation cars from 2017 using the unused chassis numbers. They are factory-built new cars, not members of the 16-car 1957 production run. |

| Label | Value |
| --- | --- |
| Built | 16 originals |
| Basis | Jaguar D-Type |
| Programme approved | 14 January 1957 |
| Body | Magnesium alloy |
| Primary market | North America |
| Continuations | 9 new cars |

## Technical specifications

### Powertrain

| Label | Value | Note |
| --- | --- | --- |
| Engine | 3'442 cc DOHC inline-six | D-Type unit; naturally aspirated |
| Induction | Three Weber 45 DCO3 carburettors |  |
| Power | 262 hp | Jaguar Classic period-specification figure; Gooding catalogues list 250 bhp |
| Gearbox | 4-speed manual |  |
| Drive | Rear-wheel drive |  |

### Structure and running gear

| Label | Value | Note |
| --- | --- | --- |
| Structure | Central monocoque with tubular front frame | D-Type architecture |
| Body | Magnesium alloy | Jaguar's stated 1957 construction |
| Front suspension | Independent double wishbones | torsion bars and tubular dampers |
| Rear suspension | Live axle | trailing links and transverse torsion bar |
| Brakes | Four-wheel Dunlop discs | Plessey pump |

### Road conversion and identity

| Label | Value | Note |
| --- | --- | --- |
| Windscreen | Full-width chromed frame | with wipers and side screens |
| Body changes | Passenger door; tail fin removed | cockpit divider also removed |
| Road equipment | Bumperettes and folding hood |  |
| Original production | 16 XKSS roadsters | Jaguar's headline count; Gooding records two further customer D-Types later factory-converted |
| Continuation production | 9 new cars | built by Jaguar Classic from 2017; distinct from the 1957 originals |

### XKSS register

4 documented · public records only. Private, unpublished and member-only chassis files are omitted.

| Year | Chassis | Colour | Provenance | Last public sale | File |
| --- | --- | --- | --- | --- | --- |
| 1957 | XKSS 775-21 |  | Published auction record from RM Sotheby's, 2020-10-24. | $1'985'000 · RM Sotheby's · 2020-10 | [Chassis file](https://hiconium.dev/vehicles/jaguar/xkss?file=XKSS%20775-21) |
| 1970 | P2R13979 |  | Published auction record from RM Sotheby's, 2024-01-25. | $215'600 · RM Sotheby's · 2024-01 | [Chassis file](https://hiconium.dev/vehicles/jaguar/xkss?file=P2R13979) |
| 1957 | XKSS 707 |  | Published auction record from RM Sotheby's, 2023-08-19. | $13'205'000 · RM Sotheby's · 2023-08 | [Chassis file](https://hiconium.dev/vehicles/jaguar/xkss?file=XKSS%20707) |
| 1957 | XKSS77723 |  | Published auction record from Gooding Christie's, 2022-08-20. | $1'545'000 · Gooding Christie's · 2022-08 | [Chassis file](https://hiconium.dev/vehicles/jaguar/xkss?file=XKSS77723) |

## The people behind the car

### [Sir William Lyons](https://hiconium.dev/people/sir-william-lyons)

Programme decision · Jaguar Cars

Approved the conversion of 25 remaining D-Types into road-going XKSS cars on 14 January 1957.

### [Malcolm Sayer](https://hiconium.dev/people/malcolm-sayer)

D-Type body and aerodynamics · Jaguar Cars

![Portrait of Malcolm Sayer](https://hiconium.dev/images/cars/jaguar-xkss/people/malcolm-sayer.jpg)

Designed the D-Type body that the XKSS retained, using aerodynamic calculation and wind-tunnel work rather than conventional styling practice.

### [William Heynes](https://hiconium.dev/people/william-heynes)

D-Type structural engineering · Jaguar Cars

![Portrait of William Heynes](https://hiconium.dev/images/cars/jaguar-xkss/people/william-heynes.jpg)

Jaguar's chief engineer; the Heritage Trust attributes the D-Type structure beneath the XKSS to Heynes and chassis engineer Tom Jones.

## Member instruments

A HICON Bid is a confidential expression of buying interest on this file. It is not a binding purchase, and HICONIUM holds no funds. [Sign in](https://hiconium.dev/sign-in) to place one. Garage files for an owned chassis are member records and are not listed here. [How membership works](https://hiconium.dev/membership).