Allard J2 With The Chrysler Hemi Engine

This past fall, September 15, 2012, I posted a brief story on this website about an Allard J2 with a Ford flathead V8 engine that had been fitted with Ardun Heads.  I noted at that time that other engines had been used in the Allard J2 cars.  One of the engines used was the 331 cubic inch Chrysler Hemi engine.  I saw  an Allard with this engine at the Newport, Rhode Island Concours show in 2008.

Allard J2 With The 331 Chrysler Hemi V8 Engine

These Chrysler Hemi engines had significant more power than the Allards with the flathead Ford V8 engines, even those with the Ardun Heads.  The flathead Fords with the Ardun Heads had horsepower in the 140 to 150 range.  The standard Chrysler 331 hemi engine had 180 horsepower.  Some Allard J2 cars were fitted with the Overhead Valve Cadillac V8 engine, but that engine at about 140 to 150 horsepower was also less than the Chrysler Hemi engine.

Allard J2 At The Glenmoor Gathering

The Allard J2 was designed to be a race car, but as can be seen from these images, the Allard J2 would be a great car to take on the road.

This Chrysler Hemi Has Some Carburetion Upgrades

While the 331 Hemi looks like a big engine, it was a very weight efficient engine at that time.  For example, if the 180 horsepower 1951 Chrysler 331 cubic inch hemi engine is compared to the 135 horsepower 1950 323 cubic inch Chrysler flathead 8-cylinder engine, then it can be seen that the  hemi engine is lighter (685 pounds to 722 pounds) and weighs in at 5.18 pounds per horsepower generated compared to 7.58 pounds per horsepower produced by the flathead 8-cylinder engine.

Standard, Unrestored Chrysler 331 Cubic Inch Hemi V8

This first FirePower engine, used from 1951 to 1955, had a bore of 3.8125 inches and a stroke of 3.625 inches for a piston displacement of 331 cubic inches. Most of these engines used a two-barrel carburetor and produced 180 hp.

The 331 engine was used in the following vehicles:

• 1951–1955      Chrysler New Yorker
• 1951–1954      Chrysler Imperial and 1955 Imperial 1951 Chrysler Saratoga (optional)
• 1952      Chrysler Saratoga Club Coupe (optional)
• 1952      Chrysler Imperial Parade Phaeton
• 1955      Chrysler 300

Cross Section Of The Chrysler 331 Hemi Engine

The 331 Chrysler Hemi that was available in the 1955 Chrysler 300 had a camshaft that was based on the 1954 Cunningham Le Mans car and fitted with two four-barrel carburetors produced 300 horsepower.  This was a substantial improvement to the 180 horsepower when it first appeared.  Therefore racers could get a lot more horsepower out of the Chrysler Hemi if they wanted to do so.

Right-Hand Drive Illustrates The Allard J2’s English Origin

I don’t have any performance figures for the Allard J2 with the 331 cubic inch Chrysler Hemi V8, but it is safe to say that with some engine modifications, then the Allard J2 would have very impressive performance.