The First 1967 383 A-Body, 'Barracuda or Mr. Norms's Dart'

Carl,

The #915 1967 440 Cylinder Head, giving you a larger exhaust valve, larger ports, and
heavier valve spings - alone would have made maybe a only +10 HP with the stock
exhaust manifolds.

But, tubular headers would have let that 383 'breathe', and probably pushed out
an additional 25 Horsepower.

For note, the 1967 383 engine had a 325 Horsepower rating in a free-flowing exhaust
B-Body. But, as well all know, the 383/325 Horsepower was overrated by the factory,
and was actually closer to 295 HP.