68dart340
Member
Does a stock early 340 ACTUALLY make? Has anybody dyno'd one?
How much power..
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Vs29H1B
Well-Known Member
In either 1968 or 1969 a 340 powered Plymouth Barracuda won it's respective NHRA stock eliminator class.
As you probably know, the factory rated the 1968 - 1971 340s at 275 BHP.
NHRA re-factored the horsepower rating to 320 in factory trim.
There have been a number of attempts by various magazines to verifiy horsepower ratings for engines in full factory trim (all powered accessories installed, etc.). The 340 was one of only a few factory engines that actually generated the factory spec. horsepower / torque ratings.
Figure a 1968 4 speed equipped 340 car (i.e. Dart/'Cuda) made the most factory horsepower, because the cam in that first year was a bit more stout than the following years. Federal Emissions requirements became increasingly tighter from 1967 on-ward, so car manufacturers were left to retard ignition timing, lean out carbs, and generally make the cars run in a compromised state from delivery by the car dealers. Most buyers of high performance cars re-curved the distributor timing advance curve, and either re-set(tuned) or re-jetted the carbs, shortly after taking delivery.
I had a 1969 Dart Swinger 340 built in September 1968 that had the 1968 cam, that was verified when I pulled down the original engine in 2000. The engine was strong in the lightweight Dart Swinger body, with headers and a good carb re-jet, the 340 ran great!
As you probably know, the factory rated the 1968 - 1971 340s at 275 BHP.
NHRA re-factored the horsepower rating to 320 in factory trim.
There have been a number of attempts by various magazines to verifiy horsepower ratings for engines in full factory trim (all powered accessories installed, etc.). The 340 was one of only a few factory engines that actually generated the factory spec. horsepower / torque ratings.
Figure a 1968 4 speed equipped 340 car (i.e. Dart/'Cuda) made the most factory horsepower, because the cam in that first year was a bit more stout than the following years. Federal Emissions requirements became increasingly tighter from 1967 on-ward, so car manufacturers were left to retard ignition timing, lean out carbs, and generally make the cars run in a compromised state from delivery by the car dealers. Most buyers of high performance cars re-curved the distributor timing advance curve, and either re-set(tuned) or re-jetted the carbs, shortly after taking delivery.
I had a 1969 Dart Swinger 340 built in September 1968 that had the 1968 cam, that was verified when I pulled down the original engine in 2000. The engine was strong in the lightweight Dart Swinger body, with headers and a good carb re-jet, the 340 ran great!
Mopar Muscule did a 340 build up and got a slightly better HP reading. Not much. A few ponies more. It appears the factory rated it correctly. At least according to there dyno at the time.
M
mopar1962
Guest
trap speed tells all
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