1968 Showdown 68' Barracuda 340-S vs. 68' 383 Road Runner

[Paul Ceasrine]

A battle of 1968 Mopar 'Musclecars'

The Plymouth Barracuda 340-S, also known as the 'Mini-Hercules'

Listed at 340/275 HP, the #3110 lb. Fastback was one the quickest Pony-style Musclecars.

Underrated at 275 HP, the NHRA re-factored the 340 to 310 Horsepower before the 1968
season got underway.

Which put the Barracuda in the {10.00 to 10.49 Wt/Hp) break of E/S or E/SA, with a factor of 10.03 Wt/Hp.
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The 'new' and heavily marketed 383 Road Runner, featuring some improvements to the steady and durable
383 engine, was now rated at 335 HP.

The Road Runner was a 'bare boned and trimmed down' Belvedere, with performance upgrades which included;
A) Windage Tray
B) Camshaft and Valve Springs from the 440 High Performance
C) Exhaust Manifolds from the 440
D) Secondary Exhaust Pipes from the 440
E) 7-Blade Fan, and Viscous Drive Fan-Clutch

The 'Pillared Coupe' weighed in at a relatively light #3424 lbs for a B-Body, and the Road Runner factored in at
10.22 Wt/Hp, which also put the Bird in the NHRA E/S or E/SA Class.

[jims5600]

Paul I would bet that not many people forgot or didn't know how quick
those 340 's where. A very strong running engine.

[Skypower]

I'll take 340 in this deal. I have had many 340
Cudas and they run like scalded dogs.

[Paul Ceasrine]

On paper, it liked looked like the 383 Big-Block Road Runner should have handled the 'Mini-Hercules' 340.

But wiser heads knew, the 'High-Reving' 340 was quicker in the 1/4 Mile.

Unfortunately, Mopar only offered each car with a 'one-size-fits-all'
340/275 HP and 383/335 HP as the only engine packages.

For Gear-Ratios,
* Standard Gears = 3.23
* Optional Performance Axle = 3.55

If you were lucky enough to know someone in Performance Sales at the
Regional Zone Office, they could finagle the factory to install a set 3.91
Gears w/Sure-Grip for you. Of course for an additional $144 for any 'so-called' connected Dealer only.

Next Up,,,,,,,,,Head-to-Head

[Jeff Lee]

I've had many 340 cars, A body and E body. I'll take the 340 A body over the 383 B body any day!
My favorite line from potential opponents on the street "Yea, I've got a 454" To which I would say "yea, this 340 is going to put you to shame!" And it always did...

[mopar68]

Presuming you're talking about cars in Pure Stock trim, I say it all depends on who's tuning and driving it. If it's Sox & Martin-prepared with Ronnie Sox behind the wheel vs. some lesser entity preparing and driving the 340 Barracuda, especially if they're both 4-speed cars, my money's on the Road Runner.

M68

[Paul Ceasrine]

Pistol Pete,,,,,,,,,,,, My Mopar Brother

We ran several of them, off the Meadowland Chrysler-Plymouth Dealership lot, and the Barracuda 340-S was quicker, in every way.

The below results were from Jerry Gross, Chrysler Technician who tested many Factory Cars.

Tested Average

1968 Barracuda 340-S

* 4-Speed w/3.23 Gears ............. 14.73 @ 96.7 MPH
* Automatic w/3.23 Gears.............14.89 @ 95.1 MPH

* 4-Speed w/3.55 Gears............... 14.44 @ 97.4 MPH
* Automatic w/3.55 Gears............. 14.66 @ 96.8 MPH

1968 383 Road Runner

* 4-Speed w/3.23 Gears............... 15.01 @ 94.2 MPH
* Automatic w/3.23 Gears............. 15.12 @ 93.1 MPH

* 4-Speed w/3.55 Gears............... 14.74 @ 98.0 MPH
* Automatic w/3.55 Gears............. 14.86 @ 95.2 MPH

Remember too, the Barracuda had E70 x 14" Tires, and the Road Runner was equipped with F70 x 14" Tires.

More To Come,,,,,,,,,,,,

[Curt Rees]

Since I was fortunate to own both and ran both at Marion, SD, I will weigh in on the subject. I changed the gears from 3:55's to 3:91s in my 1968 Purple RR. It would run 14:70s with NO prep other then checking the air in the tires. On a good day, it would get into the 14:50s. That ET was good enough to get several trophies in the pure stock classes of the day. Army called and I sold it.

As I have referenced in other posts, I ordered my my 1969 '340 Cuda with a 4 speed and 3:91 gears. It was consistent in th 14:50 range and on a good day into the 14:40s. Again, no prep other then checking the air in the tires. Those times were again good enough to take home several trophies.

Marion, SD was not a sea level track at the time. Elevation is 1300'. So the cars would probably have been quicker at a sea level track.

I remember some of the Plymouth ads being run showing low 14s for the RR and high 13s for the 340. This was I believe after some Sox and Martin prep! In real life, no.

I think some distributor and carb work, both cars would have picked up a couple of tenths. I did not do either.

The 2nd owner of the Cuda, put on a set of headers, slicks and jetted the carb and recurved the distributor and ran 13:70s. He did replace more then one clutch!

If I remember correctly, the 68 340 4 speed Cuda had a better cam then the automatic. I think that was not the case in 69. The cams were the same in both the 4 speed and the auto, with the 68 auto being standard. Paul might be able to confirm this.

#5457

Curt Rees

[Paul Ceasrine]

Curtis,

Correct on the 1968 Camshafts

4-Speed
.444 /.453 Lift ~ 276*/284" Duration ~ 52* Overlap

Automatic
.430/.444 Lift ~ 268*/276* Duration ~ 44* Overlap ~ 114* Center-Line

Though the NHRA has a different variation.

[Jeff Lee]

Back in the late '70's, a buddy Dean had a '69 Swinger 340 4-speed & 3.91's. Bone stock with bias ply tires. He worked the distributor and jetting. Shimmed the factory rockers. It was a consistent 14.00 car and ran in the 13.90's on a cool day with good barometric pressure.
He also had a '70 440-6 Road Runner with 727 and 4.10's. Same story on that car. He got it down to 13.40's on bias ply tires.
You should have seen the acid dipped, major lightening on every component '64 Signet he had with a 340 & 4-speed! It was a former street racer and my buddy Dean had a stock '69 340 with fender-well headers, 4-speed and 4.56's's in it. That ran 11.70 as I recall. A warmed over 340 (w-2 heads on a stock short-block, Purple Shaft cam, Torker). I think that ran 10.70's.
Car was feather light!
He would have loved Pure Stock racing but it wasn't around then.