The 3½ litre



3½ LITRE REGISTER by John Oliveira (Car Register number 30 published in 2001)

The 3½ Litre or Model SA25.63 was introduced at the 1935 Motor Show for the 1936 season. The second question I am often asked (after “what Alvis do you own?”) is “what is a 3½ Litre“; not very surprising when only 62 examples were produced making it one of the rarest of Alvis models.

It is one of the 6-cylinder ‘sporting’ models which Dave Culshaw has described as being evolved by careful selection from the parts bin. Two ‘new’ units were in fact employed. The chassis was effectively an Speed 20 SD stretched to 10′ 7″ wheelbase but retaining the Speed 20 SD back springs (which were lengthened by a foot when the Speed 25 came along) and adding a solid floor plate filling the area between the gearbox and the batteries.

The engine (later used for the Speed 25) similarly looks like a stretched Speed 20 unit, with a 7-bearing crank, looking back to that model by not having a thermostat and bypass.

Running gear, engine ancillaries and gearbox are shared with other models, but the radiator was about 4″ taller than the Speed 20 or 25 and the bodyline therefore that much more imposing. The grille is a bolt-on affair with a large number of narrow vertical slats, easily distinguishable from the other big sixes.

Unlike the Speed 20, the model was available only as a chassis. Coachbuilders associated with Alvis; Mayfair, Mulliner, Charlesworth, Vanden Plas, etc. put out body designs for the new chassis and there are therefore groups of cars which have bodies to the same design, but there were no “off the peg” cars such as were available for the Speed 20 and indeed for the Speed 25. Every body was individually ordered by the customer. Some bodies were one-offs, usually by companies not normally found building bodies for Alvis Cars.

I believe that Alvis were trying to achieve a separation between the “standard” Speed 20 package of chassis and catalogued body and a more powerful chassis aimed at clients with a deeper pocket who wanted an individual tribute to their taste and discernment. The extra length and power would give body designers more scope to extend their imaginations. The mixture was perhaps not quite right, especially in the horsepower department, and was made over for the 1937 model season. The Speed 25 SB replaced the Speed 20 as the “off-the-peg” model and the 3½ turned into the 4.3, also only available as a chassis.

The power may well have been needed to compete with the likes of Bentley, Talbot and Lagonda; the increasing weight and sophistication of bodywork affecting all makers. Of the 44 3½ Litre bodies of which the style is known, 32 were saloons. It would be interesting to know what the proportion was for Speed 20’s, Fireflies and Eagles of the immediately preceding years. My own supposition is that open body styles were becoming markedly less popular in the mid thirties. If this is so Alvis may have underestimated the need for more power to improve performance while carrying altogether heavier bodies.

Build sheets show that the first delivery from the factory was on the 23rd July 1935 and continued steadily until 25th August 1936. Four months later, on 17th December, a final example was built for Sidney Guy of the Wolverhampton truck making firm. Why he didn’t have a Speed 25 or a 4.3 is not known. The car wears a Charlesworth saloon body with valances in place of running boards, such as did not appear on the Speed 25’s until 1939 – another little mystery. (The Guy family are rumoured to still possess documentation on the car; if anyone can turn it up, we may get some answers.)

Production was laid down in one batch between 23rd July 1935 and 17th December 1936.
Chassis Number 13086 – 13155 inclusive making 70 in total.
8 Chassis, 13148 to 13155 and engines thereto were laid down but not completed. The chassis may have been re-numbered and uprated into the first 4.3 litre batch. The engines 13598 to 13605 were diverted to a batch of Crested Eagles.
16 Charlesworth – Dhc 2 Saloon 6 unknown 8
15 Vanden Plas – Dhc 1 Saloon 10 Tourer 3 unknown 1
12 Mayfair – Coupe de Ville 2 Saloon 3 Sedanca 2 unknown 5
8 Unknown
6 Arthur Mulliner – Saloon 3 unknown 3
4 Freestone & Webb – Saloon
2 Bertelli – Saloon
2 Mann Egerton – Dhc 1 Saloon 1
1 Gurney Nutting 2 door Saloon

1 Lancefield – Dhc
1 Arnold – unknown
1 Martin & King Saloon (Australia)
1 Mulliner Saloon

John Oliveira in 2013 at East Anglian Alvis day with CXM 98
John Oliveira in 2013 at East Anglian Alvis day with CXM 98

John’ s ownership of CXM 98 is recorded in  FIFTY YEARS BEHIND THE RED TRIANGLE

3½ Litre SA 25.63 Vanden Plas 3449 Tourer – photo John Fasal via Dave Culshaw and Wayne Brooks. First delivered to the Maharajah of Mayurbhanj it has remained in India and a photo of its current state can be found at number 22 on  Pebble Beach 2018
2012 Gurney Nutting 010
The Gurney Nutting 3.5 litre at IAD 2012 – AAT photo



The Bertelli SA25.63 with 4.3 engine.


Autocar April 24th 1936 “Follett Bodied” Mayfair delivered to Braintree Motors for Mrs Rolt

Nick Simpson thinks this is either a 3 1/2 Litre or a 4.3. Its a Vanden Plas Pillarless saloon. The unusual features that may help with further identification are twin air vents on the back edges of the bonnet top panels and it has twin spare wheels.
My guess is its a late 3.5 litre or early 4.3 Litre. Early versions had the front wings curved tight behind the front wheels – this has the later style wings. 4.3’s from chassis about 13177 had the spare wheel mounted in a can on the boot lid.
What do you think?

Nick Simpson says the style and back-end ‘lift’ are unmistakeable Mulliner. I think this on is a one-off, probably owned by Louis Antweiler, the Chairman of Mulliners. Its a 3 1/2 Litre chassis – the give-away is the bolt-on stone guard on the radiator. This car also appeared in a road test in Country Life in 1935.
Where is it now?

The four Freestone and Webb saloons were commissioned by Alvis and loaned to journalists resulting in several articles full of praise for the new model.


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