1968 Plymouth Barracuda Formula S

1968 Barracuda 340 -4 speed , Formula S. Factory Air Conditioning car, air conditioning is currently not installed but I have the compressor, etc. Will need inspection for out of province. Just brought in from USA, I did not bring this in to sell it, my knees are shot and I have a hard time with the clutch.

Numbers matching 1968 Barracuda Formula S, Factory 340 – 4spd.
Restored in 2005 and then only has 5000 miles since.

In 1968, there were 45,412 Barracudas produced. Of those 45,412 only 2,857 were a 340 Formula S.

This car is parked for the winter inside a heated garage.

MotorTrend

Everyone knows Mopar factory horsepower ratings in the muscle car era were the most honest of them all; if the 440 Magnum was advertised with 375 horsepower, that’s what it made. And let’s not forget how the 426 Street Hemi was cleverly under-rated by the ad guys. Rather than tout its nearly 500 horsepower at 6,000 rpm (and give the safety watchdogs even more to chew on), Chrysler intentionally stopped counting at 5,000 rpm, where 425 horsepower was legitimately on tap.

But what about the 340, launched in 1968 specifically for lightweight A-Body installations, then spread throughout the B- and E-Body performance models in 1970-’73? Did it really make “only” 275 horsepower in pre-’72 mode with 10.5:1 compression and 2.02-inch intake valves? And what about the 1970 SCCA-inspired 340 Six Pack installed in those special Challenger T/A (2,399 built) and AAR ‘Cuda (2,724 built) E-Bodies? Was the claim of its 290 horsepower (5,000 rpm) and 345-lb-ft (3,200 rpm) realistic?

We’ve always wanted to know, and tagged along with Donnie Wood and Steve Chmura of R.A.D. Auto Machine to watch the assembly of a nearly stock-specification 340, and the subsequent dyno test comparison with factory 4-BBL and 6-BBL induction setups. The results was surprising and not surprising at the same time.

On factory claims of 275 horsepower at 5,500 rpm and 340 lb-ft (3,200 rpm), we got 320 horsepower at 5,500 rpm and 368 lb-ft at 3,500 rpm. So it’s clear Mopar understated the facts by 45 horsepower and 28 lb-ft. Then we replaced the manifolds with a set of headers and got 352.1 horsepower and 395.9 lb-ft (at 3,200 rpm)—77.1 horsepower and 55.9 lb-ft higher than published peak claims.

For some in the dyno room, the elevated power readings came as a surprise. Let’s remember, the 340-powered 1968-’69 Dart GTS/Swinger 340 and Barracuda Formula S/’Cuda 340 A-Bodies were initially marketed as budget or “junior” supercars, battling stuff like the SS350 Nova (295 horsepower), W-31 Olds 350 (325 horsepower), Pontiac 350 HO (325 horsepower) and 351 Windsor four-barrel Mustang (290 horsepower). There it would have been great to advertise its real 300-plus horsepower capability against the competition.

But on the other side of the coin, when sold beside 383-powered Road Runners and Super Bees at Plymouth and Dodge dealerships nationwide, the difference between their 335 horsepower rating and the 340’s 320 horsepower may have led to internal competition, and reduced B-Body sales. It’s all water under the bridge at this point, but the 320 horsepower we observed explains a stock 340’s well documented ability to toss any A-Body well into the 14-second zone at the strip. So what about the Six Pack?

Testing RAD’s patience, we asked them to swap intake and exhaust systems on the dyno so we could get more answers. Going back to the factory stock cast-iron exhaust manifolds, a Six Pack replaced the four barrel and we got 356 horsepower at 5,500 rpm and 382 lb-ft at 4,000 rpm. Again, Chrysler’s 1970 claim of 290 horsepower at 5,000 rpm and 345 lb-ft at 3,200 rpm was bettered by 66 horsepower and 37 lb-ft. Finally, we replaced the headers and watched it grow another 20.1 horsepower and 26.9 lb-ft with readings of 376.1 horsepower at 5,500 rpm and 408.9 lb-ft at 4,000 rpm.

So the next time you see a stock 340 or 340 Six Pack, don’t be fooled into thinking it’s a sub-300 horsepower muscle car wannabe. Follow along as we assemble a 340 small-block and put it to the test.