Dan,
340/275 HP, horsepower re-factor to 310 HP.
Not sure on how the NHRA knew, but they did.
Chrysler Performance was informed of the rating back in December
1967.
Thats when the Southern California Dodge Dealers started building
the E/S Dart GTS that Bill Shrewsberry raced.
The #3150 lb. 68' 340 Dart GTS and 340 Barracuda's still were successful in E/S and E/SA, running 12.80's.
Imagine them running in G/S in 1968,,,,,,,
