Vintage CL Road Test: 1968 Plymouth Barracuda 340-S – “Best Yet Of The Barracuda Brigade”

When the second-generation Plymouth Barracuda debuted for 1967, it offered an awkward choice between too much engine (the bulky, heavy 383) and not quite enough (the smaller 273 V-8 or Slant Six). For 1968, Chrysler-Plymouth redressed this shortcoming with the new 340, one of the hottest small-block V-8s of the muscle car era. In December 1967, Car Life tested a Barracuda Formula S with the new engine and called it “a real value in the field of high-performance automobiles.” Here’s what they had to say about it.

New Fish on the Block

Car Life had previously tested two 1967 Barracuda hardtops, one with the 225 cu. in. (3,682 cc) Slant Six, the other a Formula S, with a stiffer suspension and the four-barrel version of Chrysler’s 273 cu. in. (4,482 cc) LA-series small V-8, rated at 235 gross horsepower. Both had adequate performance with the excellent TorqueFlite automatic — the six went from 0 to 60 mph in 13.6 seconds, the 273-4V car in 9.2 seconds — but they didn’t qualify as hot stuff by the standards of 1967.

Another option, which Car Life drove only briefly (I don’t think they ever did a full road test), was the bigger 383 cu. in. (6,277 cc) B engine. This was a bulkier, heavier engine than the LA-series V-8, and it had to be shoehorned into the Barracuda engine bay, precluding the installation of air conditioning, power brakes, or (until later in the run) power steering. Worse, the more restrictive exhaust system cost about 40 gross horsepower, dropping the 383’s advertised rating to an unexceptional 280 hp (300 hp for 1968).

 

The 383 made the Barracuda quicker than the 273 did, but not enough quicker to compensate for its drawbacks in street driving — a letdown considering that the small-engine Barracuda Formula S was regarded as one of the nimbler pony cars. Martyn L. Schorr of High Performance Cars called the Barracuda 383 “a clumsy around-town handling bomb due to the extra weight planted over the front wheels” and complained that “it still lacks the super-punch of a supercar.”

 

Of course, the rival Ford Mustang 390 presented similar problems, but what the Barracuda really needed was a good middleweight engine that wouldn’t overcrowd the engine bay or overcrowd the chassis.

Enter the 340. Introduced for 1968, the 340 cu. in. (5,567 cc) V-8 was a development of the LA-series, but it wasn’t simply a bored-out version of the 273 or 318 cu. in. (5,204 cc) versions. In designing the 340, Chrysler had made extensive use of thinwall casting and precision foundry tricks — not to reduce the engine’s weight, but to allow the largest bore size and biggest ports that could be accommodated within the existing block and head dimensions.

 

The text refers to the larger valves, but it doesn’t adequately convey just how much the 340’s breathing had been opened up compared to its milder siblings:

Port and Valve Sizes,
Chrysler LA-Series 273/318 vs. 340

Valve/Port	273/318	340	Percentage Change
Intake port area, sq. in.	1.70	2.20	+29.4 percent
Intake valve diameter, in.	1.78	2.02	+13.5 percent
Total intake valve area, sq. in.	19.91	25.64	+28.8 percent
Exhaust port area, sq. in.	1.25	1.70	+36.0 percent
Exhaust valve diameter, in.	1.50	1.60	+6.7 percent
Total exhaust valve area, sq. in.	14.14	16.08	+13.8 percent

 

Car Life noted:

To emphasize the adequacy of the new valve sizes, comparison with the 350-cid Chevrolet engine, long touted for its exceptional breathing ability, is in order. The Chevrolet features valves of 1.94 and 1.50 in. diameter, intake and exhaust. Thus, the new Barracuda 340 engine has exceptionally large valves. Substantial high-speed output was evident in the vehicle’s performance.

The 340 engine also had hotter camshafts — cams for manual- and automatic-transmission applications were slightly different — along with a double-level intake manifold, low-restriction exhaust manifolds, a windage baffle in the oil pan, and a viscous torque fan drive that reduced the fan’s power consumption by 7.5 hp at 5,000 rpm.

 

With 10.5:1 compression and a bigger Carter AVS carburetor, Chrysler rated the 340 at 275 gross horsepower and 340 lb-ft of torque. This was clearly conservative, leading the NHRA to “factor” the engine to 290 hp for classification purposes. Chrysler didn’t initially release net ratings, but they did say the 340 had 40 percent more net horsepower than the 273-4V, which was advertised at 235 gross hp. In 1971, Chrysler finally published net ratings of 235 hp and 310 lb-ft of torque, although by that time, they had standardized the milder automatic cam and slightly lowered the compression ratio. In his 1983 book American Supercar, Roger Huntington estimated that the 340 in the 1968 Car Life Barracuda test car had about 290 net horsepower, which sounds too high to me; my guess would be something like 260 to 270 hp.

 

In any event, the 340 gave the Barracuda’s performance a shot in the arm. Said Car Life:

Low-speed torque was relatively weak, as it should be in an engine installed in a passenger car with forward weight bias and non-dragstrip rear tires. Full throttle could be used on takeoff, on dry pavement, with slight wheelspin. This was followed by a long, strong pull up to 5500-5800 rpm. This is an example of an engine well suited to a car. This type of performance makes much more sense than the 383-cid Barracuda package that features gobs of low-speed torque to turn rear tires into smoke, yet runs out of breath at 4500 rpm.

Times and speeds in the quarter-mile were eye-openers for a relatively small engine. With the usual two passengers and test gear load, the Barracuda 340-S buzzed through the lights in the high 14-sec. bracket at speeds around 95 mph. Both elapsed time and top speed were substantially superior to a 383-engined 1967 Barracuda briefly examined by CAR LIFE.

An added bonus with the new 340-cid engine is a weight saving of approximately 100 lb. Thus, handling and traction are noticeably improved. Also, since the 340 has external dimensions similar to the 273. standard power steering equipment can be fitted, a worthwhile addition to the car, and one which was impossible with the much larger 383-cid engine.

 

The 340 was not quite the ultimate weapon in small-block V-8 power: The 302 cu. in. (4,942 cc) SBC in the limited-production Chevrolet Camaro Z/28 was significantly more powerful, but also much more high-strung, concentrating its power near the top of its rev band. A 340 Barracuda was not nearly so peaky, and it provided a better balance of performance for real-world use. As Car Life explained:

Excellent quarter-mile performance of the 340-S complemented its exceptional high-speed cruising ability. The new 340-cid engine is very flexible, and runs freely at high engine speeds. Cruising at 4000 rpm was quite effortless, although such speeds are grossly illegal in most states. Still, it’s significant that the 340-S chassis was capable of smooth, steady performance and good stability at sustained 100-mph speeds. This certainly indicates satisfactory performance at normal 60-70 mph limits.

High average speeds were aided by the abundance of passing power available in the 340-S. Kickdown provided plenty of acceleration for pulling around slow traffic in a minimum distance.

A point worth emphasizing here is that, as the spec table reveals, the CL test car TorqueFlite and a mild 3.23 axle. Given the 340’s appetite for revs, a higher numerical axle ratio would have been a boon to serious dragstrip work, but for street use, keeping engine speeds to 3,000 rpm or less at legal highway speeds was easier on the nerves, and a bit easier on gas — Car Life averaged 13.5 mpg with their air-conditioned test car.

 

Unlike the heavy 383, the 340 weighed no more than the 273-4V — 539 lb dry — and thus didn’t prevent the Formula S chassis from showing what it could do on a winding mountain road:

The Barracuda, while not a sports car, negotiated many curves at speeds that would give some accepted “sports cars” considerable strain. The Barracuda is relatively large and heavy, compared with other GT cars, and these characteristics are evident when driving through tight curves. A lack of agility is apparent, but driver confidence remains intact. The driver soon gets the feeling that it would take some incredible occurrence to make the Barracuda lose its grip on the pavement.

Fairly strong understeer is dominant, although slow turns can be taken in an oversteering attitude by applying large amounts of power to the rear tires. One of the prime attributes of the 340-S was that, even with closed throttle in a fairly hard turn, the car refused to roll, tuck a wheel under, or slide smartly off the road.

 

However, the CL did offer some qualifiers about the road manners of the Formula S package:

Much of the excellent stability of the 340-S apparently has been achieved through high spring rates. This became obvious when traversing the first stretch of bumpy roadway. The 340-S was quite harsh over small-amplitude irregularities, though the firm damping was appreciated on undulating highways. It would seem that some additional suspension system compliance could be applied to the Barracuda to lessen ride harshness without losing a significant amount of handling precision. If this cannot be accomplished, then CAR LIFE would rather have the package left alone.

 

Although their test car had the optional front discs (the blue car in the photo has drums), the Car Life editors were none too impressed with the Barracuda’s stopping power:

On seeing the car for the first time, it appeared that the combination of disc front and drum rear brakes, with no power assist, would be an excellent system for the sporting driver. In actual testing, fade resistance was rather poor, for a disc/drum system, and pedal efforts to maintain high deceleration rates with well-warmed brakes bordered on the fantastic. To reach a deceleration rate of 16 ft./sec.² on the third panic stop from 80 mph required both feet of a reasonably strong test driver. Concern over seatback failure was voiced during such Herculean brake applications. Apparently a booster is necessary to stop a 3000-lb. vehicle with a reasonable-sized disc/drum system.

Concerns about pedal effort were one of the reasons Detroit had dragged its feet on offering disc brakes in the first place: The self-energizing effect of drums made power assist less essential, whereas unassisted discs could be annoying heavy even on cars hundreds of pounds lighter than the Barracuda (which had an as-equipped curb weight of 3,470 lb).

Judging by the previous Car Life Barracuda road tests, a brake booster probably still wouldn’t have produced outstanding stopping ability because Chrysler hadn’t yet incorporated any kind of proportioning valve to delay rear-wheel lockup in a hard stop. Rear lockup had been a problem on both of the two previous Barracudas tested, and a Fury III convertible Car Life had tested in July 1967 had gotten sideways on its first 80 mph to 0 test stop, which they said “was a memorable, vividly traumatic experience for the testers” that would probably have ended in disaster if it had been on a public road rather than a test track. Their 1967 Barracuda comparison had remarked that a proportioning valve “would be well worth paying for, were it offered for sale with Plymouth Division cars.” In 1968, it still was not.

 

Nonetheless, Car Life was generally satisfied with the Barracuda 340-S. They were annoyed that the front seats didn’t adjust for rake, finding the upright seatbacks “caused considerable discomfort on long trips,” and their test car suffered a power steering pump failure during their test, but they thought the fit and finish was pretty good and the interior “attractive and fairly functional.”

 

After a long highway trip, the editors remarked:

Long days behind the wheel brought a real appreciation of the Barracuda’s high-speed stability, and the air conditioning system afforded genuine comfort over long stretches of 110° desert terrain.

One could not help wondering how long the average European GT car could stand up to this type of long, hard touring. The Barracuda gave a feeling of effortless performance, regardless of the demands placed on it. Somehow it seems that American cars offer more for the American driver on American roads. In the Barracuda 340-S, the driver can enjoy an exceptional car in many ways, an adequate car in nearly all ways, and a real value in the field of high-performance automobiles.

 

 

Turning attention once again to the data panel on the bottom of the previous two pages, we find that while the 340 Barracuda wasn’t quite a match for a Firebird 400, it could easily dispatch most of its pony car rivals, including some with bigger engines. Here’s a summary from various Car Life road tests:

1968 Plymouth Barracuda 340 vs. 1967 Ford Mustang 390 vs. 1967 Chevrolet Camaro SS350 vs. 1967 Pontiac Firebird 400

Performance	Barracuda 340	Mustang 390	Camaro SS350	Firebird 400
0–30 mph	3.0 secs.	3.4 secs.	2.9 secs.	2.9 secs.
0–60 mph	7.0 secs.	7.8 secs.	7.8 secs.	6.5 secs.
0–100 mph	16.4 secs.	20.5 secs.	19.8 secs.	15.5 secs.
Standing ¼ mile	14.97 secs. at 95.4 mph	15.5 secs. at 91.4 mph	15.8 secs. at 89.0 mph	14.7 secs. at 98.0 mph

 

The 340 Barracuda’s performance also made for an instructive contrast with the rarer and more specialized Camaro Z/28, which Car Life tested in July 1968. The Z/28 was 115 lb lighter and had a close-ratio four-speed with 4.10 axle against the Plymouth’s TorqueFlite/3.23 combination. However, see how they ran in Car Life hands:

1968 Plymouth Barracuda 340 vs. 1968 Chevrolet Camaro Z/28

Performance	Barracuda 340-S	Camaro Z/28
0–30 mph	3.0 secs.	3.5 secs.
0–40 mph	4.2 secs.	4.5 secs.
0–50 mph	5.5 secs.	5.7 secs.
0–60 mph	7.0 secs.	7.4 secs.
0–70 mph	8.7 secs.	8.9 secs.
0–80 mph	10.7 secs.	10.5 secs.
0–90 mph	13.2 secs.	12.5 secs.
0–100 mph	16.4 secs.	14.2 secs.
Passing, 30–70 mph	5.7 secs.	5.4 secs.
Standing ¼ mile	14.97 secs. at 95.4 mph	14.85 secs. at 101.4 mph
Engine revs per mile	2,590 (23.2 mph/1,000 rpm)	3,260 (18.4 mph/1,000 rpm)

 

The much higher trap speed revealed the Z/28 engine’s greater ultimate power, but even with the shorter axle and closer-ratio gears, the Camaro couldn’t catch the Barracuda until they were both past 70 mph, and you had to keep the revs up for best performance. For street use, the hot 340 was a much better compromise, and arguably the ideal pony car engine of this era: relatively light and revvy, but flexible and easy to live with.

Buyers, however, remained unmoved. Chrysler-Plymouth had sold only 62,534 Barracudas for 1967, and sales fell to 45,412 for 1968 and 31,987 for 1969.

 

When looking for additional photos for this post, I was hoping to find a 1968 Barracuda 340 Formula S with about the same equipment and color combination as the Car Life test car (which was red with a white vinyl interior, the “Rallye Instrument Cluster” (a 150-mph speedometer, trip odometer, and woodgrain dash trim), and wire wheel covers), but the Electric Blue Metallic car was as close as I could come. When I checked the production figures, I understood why: Only 1,120 1968 Barracudas were ordered with the Formula S package, and only 2,461 ’68 cars had the 340/TorqueFlite combination. Looking for a specific color/trim combination on top of that was like looking for a needle in a haystack.

 

Why didn’t the Barracuda sell better? With the addition of the 340, the Plymouth pony car now offered highly competitive performance, and its flaws were no worse than its rivals’, but that apparently just wasn’t enough for many people. Whatever the buff books implied, the big selling point for pony cars in their heyday was not outright performance but style and image, and in those areas, the Barracuda fell short.

Please understand that it gives me no pleasure to say this, because I like the looks of the second-generation Barracuda a lot (especially the hardtop), but the wheel arches were too small, the tail was a little longer than was fashionable, the front aspect seemed a bit tall and narrow, and some of the detailing was rather crude. The second-generation Barracuda body shell no longer shared many body panels with the Valiant (Milt Antonick, who was primarily responsible for the styling, said the only shared piece was now the rear wheelhouse inner), but the hot fish still hadn’t divorced itself from the structural hardpoints and proportions of its plebeian cousin — certainly not to the extent that the Mustang had separated itself from the Falcon. Judging by the sales figures, contemporary buyers could tell, and they didn’t much like it.

 

They were missing out. The Barracuda 340 Formula S might have been a runner-up in the beauty contest, but it offered the kind of performance and practicality the pony cars had always promised, but didn’t always deliver.

Related Reading

Curbside Classic: 1967 Plymouth Barracuda Hardtop – B-Side Magic (by Tatra87)
Vintage Car Life Review: 1967 Barracuda Comparison – The Tame 6 cyl. Hardtop and The Brisk V-8 Fastback (by Rich Baron)
Curbside Classic: 1968 Plymouth Barracuda Formula 340 – The Worst Selling But Best Pony Car Of 1968 (by Paul N)
COAL- 1968 Plymouth Barracuda to Volvo 122 to Bass Guitar (by Chas Glynn)
COAL: 1969 Plymouth Barracuda 340 Formula S – Heading East (by Johannes Dutch)
Vintage CL Road Test: 1969 Plymouth ‘Cuda 440 – “A Disturbing Automobile” (by Paul N)