Dart 440,
Just some information.
The 1967 383/325 HP in the B-Body cars was the same engine as in the 1967
Barracuda and Dart, excpept for a better flowing exhaust system and a true-jetted
Carter AFB (575 CFM).
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Factory Rating of the 1967 383/280 HP (A-Body)
280 HP @ 4200 RPM
400 Ft-Lbs. of Torque @ 2400 RPM
Factory Rating of the 1967 383/325 HP (B-Body)
325 HP @ 4800 RPM
425 Ft-Lbs. of Torque @ 2800 RPM
Factory Rating of the 1968 383/300 HP (A-Body)
300 HP @ 4400 RPM
400 Ft-Lbs. of Torque @ 2400 RPM
Factory Rating of the 1968 383/330 HP (B-Body, 'non' Road Runner, Super Bee, Charger)
330 HP @ 5000 RPM
425 Ft-Lbs. of Torque @ 3200 RPM
Factory Rating of the 1968 383/335 HP (Road Runner, Super Bee, Charger R/T)
335 HP @ 5200 RPM
425 Ft-Lbs. of Torque @ 3400 RPM
The difference between the 1967 383/325 HP and 1968 383/330 HP engine, was the #906 Cylinder Heads,
Deck Height, Intake Manifold, and Carter AVS Carburetor, for a gain of '5 HP'.
The difference between the 1967 323/280 HP (A-Body) and 1968 383/300 HP (A-Body) engine, was the same
identical changes, but with an improved exhaust manifold design and a better low-restriction flow exhaust piping,
for a gain of '20 HP'.
Based upon Chrylser's changes, the improved exhaust system inceased Horsepower by +15 HP.
In 1968, the Road Runner 'Camshaft and Valve Train' was 'only' available in the 383 Road Runner, 383 Super Bee and Charger.