Flat floor, outside bonnet locks and welded louvres

The point of this page

Flat floors, external bonnet locks and welded louvre bonnets are almost always described together, as though a car either has all three or none. That is wrong, and the chassis numbers show it clearly. The three changes happened at three different points, and the gap between them is not small.

The chassis numbers

The Jaguar Clubs of North America Series 1 Judges Guide is the only source the archive has found that gives all four production streams for both the bonnet locks and the floors. The numbers are unambiguous because each stream has its own prefix block.

External bonnet locks were fitted up to 850091 on right hand drive roadsters, 875385 on left hand drive roadsters, 860004 on right hand drive coupes and 885020 on left hand drive coupes.

Heel wells were introduced at 850358 on right hand drive roadsters, 876382 on left hand drive roadsters, 860176 on right hand drive coupes and 885504 on left hand drive coupes. Every car before those numbers has a flat floor.

Note the right hand drive coupe: four cars with external bonnet locks. That follows from the right hand drive coupe not starting production until July 1961, by which time the change was essentially complete.

Where the famous 500 comes from

Add the four bonnet lock figures together. 91 plus 385 plus 4 plus 20 is exactly 500. That is where the number comes from, and it is correct, for the bonnet locks.

Now do the same for the floors. On the right hand drive roadster the bonnet lock goes at 850091 and the flat floor survives to 850357, a further 266 cars. On the left hand drive roadster the gap is from 875385 to 876381, nearly a thousand cars. Totalled across the four streams, the flat floor population is somewhere around 2,416 cars, which is about five times 500.

So the widely repeated statement that the first 500 cars had flat floors and external bonnet latches is right about the latches and wrong about the floors by a factor of roughly five.

Two things follow

• Every outside bonnet lock car is a flat floor car. The reverse is emphatically not true, and there are several times as many flat floor cars as bonnet lock cars.
• The welded louvre bonnet outlives the external bonnet lock. The judging guide records welded louvres observed at least through 876160 on the left hand drive roadster, which is well past that stream's bonnet lock end at 875385.

The disagreement the archive cannot settle

Eagle gives the left hand drive roadster floor change as chassis 582, which would be 875582, against the judging guide's 876382. Those are 800 cars apart and they cannot both be right. It is possible the two sources are describing different panels rather than contradicting each other, because the guide's heading is heel wells and Eagle's wording is footwells, and Eagle separately records a second floor change, a recessed panel behind the seats added before the end of 1962. But no source the archive has found establishes that, so the disagreement stands and the flat floor total has to be given as a range.

There is a smaller disagreement on the bonnet locks. Eagle says the first 92 right hand drive and 386 left hand drive roadsters had them, against the guide's 91 and 385. That one car difference in each stream is exactly what an inclusive reading of up to produces, and both are recorded.

The welded louvre bonnet, and how to recognise one

The distinction is construction, not appearance from ten feet. On the early bonnet the louvres are pressed into a separate panel which is then spot welded into the centre section, and the flanges and centre section are spot welded to the outer skin rather than bonded. On later bonnets the louvres are pressed directly into the centre section and the flanges are adhesive bonded.

A specialist panel maker who builds these gives several checkable tells for a genuine early bonnet.

• A fibreglass heater intake with a special dish to clear the turned edge of the welded louvres
• Wider flanges, with a small tab spot welded between them
• The folded vertical edge at the rear of the valance folded outward rather than inward, which is the opposite of every other E-Type
• Deeper and noticeably crisper covered headlamp flanges
• The rear wing support spot welded directly to the skin along its whole length, where later wings are spot welded only at the ends and bonded in the middle

No chassis number for the end of welded louvre production has been found in any source at any tier. The best that can be said is that they persisted at least to 876160, and that Eagle places the change around the end of 1961.

A trap when inspecting

Factory floor panels were die forged with a distinctive pattern of stiffening webs. A car with plain flat plate let into the floor is a car with a bad repair, not a flat floor car. Since flat floor cars command a premium, this is worth knowing before you get excited about a flat looking floor.

Other early features

The aluminium centre console is the one most often misdescribed. It is principally the propshaft tunnel cover and console, not the dash top, which was vinyl covered from the start, although as many as the first thousand cars had thinner dash tops. The console ran through three variations during 3.8 production: aluminium with a dot pattern, then aluminium with a cross hatch pattern, then leather and vinyl with a cubby box and armrest.

The important consequence is that the third variation had already arrived before the 4.2 did, and the 4.2 simply inherited it. So the common shorthand that the 3.8 has an aluminium console and the 4.2 has vinyl is wrong. Plenty of late 3.8s have the vinyl console.