The 1968 interim cars

Series 1.5 is a collector term. The factory records make no such division: these cars sit inside the Series 1 4.2 chassis sequence, which the Heritage Trust guide runs to July 1968. The label survives because the cars are visibly and mechanically transitional, and because owners needed a word for a car that is plainly not a covered-headlight Series 1 and equally not a Series 2.

What changed, and why

Almost all of it came from the United States, which was the E-Type's largest market. New federal rules on lighting, interior projections and exhaust emissions arrived for the 1968 model year, and Jaguar met them with a set of changes applied from around August 1967. Several were applied worldwide rather than only to export cars, which is why a home market car of the same date carries some of them.

• Open headlights. The glass covers were deleted. This is the change everyone notices, and on its own it proves nothing, for reasons set out below.
• Rocker switches. Black plastic rockers replaced the row of metal toggle switches, in response to rules on projections inside the cabin.
• Carburettors. United States market cars took twin Zenith-Stromberg carburettors in place of the triple SU HD8 installation, for emissions compliance. Cars for other markets kept the three SUs.
• Cooling and cam covers. Twin electric cooling fans, and ribbed cam covers in place of the earlier polished ones.
• Wheels. A hexagonal knock-off nut replaced the winged eared spinner on wire wheels, again a 1968 model year United States requirement.
• Seats. Adjustable seat backs, in place of the fixed-rake earlier arrangement.

The trap: headlights alone prove nothing

A number of late Series 1 cars left the factory with open headlights while remaining otherwise wholly to earlier specification: three SU carburettors, push button starter, toggle switches, polished cam covers. These are sometimes called Series 1.25, which is a phrase of convenience with no factory standing whatsoever. How many were built has not been established, and this archive will not invent a number for it.

The practical consequence is worth stating plainly. On a car from 1967 or 1968, check the carburettors, the switchgear and the cam covers before you decide what you are looking at, then check the chassis number against the Heritage Trust ranges and against xkedata.com. A seller describing a car by its headlights is describing the least reliable feature on it.

What an interim car is like to live with

Mechanically these are late Series 1 4.2s, so the driving experience is that of a 4.2: all-synchromesh gearbox, the better servo, the reshaped seats. Two differences matter. The twin cooling fans help in traffic, which is a real gain over an early car. The twin Zenith-Stromberg installation on United States cars is generally held to give away output against the triple SUs, and a proportion of those cars have long since been converted back. A conversion is not a fault, and it is a change from original specification, which is worth knowing before you buy rather than afterwards.

How many were built

Any figure for Series 1.5 production is a figure for a category the factory did not keep. The per-body-style breakdown most often copied online lists 6,726 interim cars, made up of 1,942 fixed-head coupes, 2,801 open two-seaters and 1,983 2+2s. Breakdowns that do not split the interim cars out simply count them within Series 1 4.2 production, which is why published Series 1 totals differ by roughly that amount. The competing tables are set out in full on the production numbers page.

Common questions