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1. There was such a thing as a 383 two-barrel cam in the early 60's. Two barrel cam was 252 duration, about .390 lift. Four barrel cam was 268 duration, .430 lift

2. There is no "two-barrel cam" for late 60's 383's. Not sure about 65 or 66, but 67-70 383's ALL used the same 256/260 duration, .425/.437 lift cam EXCEPT for Road Runners, Super Bees, and 69 A body 383's. The last three used the 440 hi-po cam.

3. 383 A bodies did not use any special low rise intake manifold. ALL 62-67 383 four barrel engines used the same #1859300 intake manifold.

4. 67 A body 383's were identical to 67 B and C body 383's except for the exhaust manifolds.

5. The initial question assumes that 67 A body 383's actually had less horsepower than 67 B body 383's. Given that dyno testing of the 67 B body 383 showed that they only made 280 horsepower, that's a questionable assumption.

6. People need to look at the 67 B body 383 exhaust manifolds and compare them to 67 A body 383 exhaust manifolds. I personally don't see how the log manifolds B body 383's had can flow any better than the 383 A body manifolds, but they darn sure aren't any 45 horsepower better.

7. If you really believe the factory hp ratings, you have to believe that a 1964 383 with two-barrel carb, 252 cam, single exhaust and a factory rating of 305 horsepower is stronger than a 67 Barracuda or Dart with a 383 4-barrel, 256/60 cam and dual exhaust. Makes you wonder why the factory bothered putting a four barrel or dual exhaust on the A body 383's.

8. The 68 A body 383's are identical to the 330 horse B body 383's except for the exhaust manifolds. Both have the same 256/60 cam. Since the A body 383's are rated at 300 horsepower and B's at 330, either the A body exhaust manifolds are 30 horsepower worse or either one engine is overrated or the other is underrated.

9. The 69 A body 383's are identical to the Road Runner/Super Bee 383's except for the exhaust manifolds. Both have the 440 hi-po 268/276 duration, .450/.465 lift cam. Since the 69 A body 383's are rated at 330 horsepower, one would assume that their exhaust manifolds are only five horsepower worse than the Road Runner/Super Bee exhaust manifolds (I can actually believe that).

Problem with that theory is that the 68 and 69 A body 383 exhaust manifolds are the same, so you have to believe the same manifolds are 30 horsepower worse than B body (non hi-po) 383's one year, but only five horsepower worse than the (hi-po) 383's the next. (And of course, 440 A bodies had the same horsepower rating as 440 B bodies, so what's the deal there????)

10. Through the 1970 model year, only Road Runners, Super Bees and the 69 A body 383's (and 440's) used the 440 hi-po cam. In 1971, all 4-barrel 383's used the hi-po cam. Two barrel 71 383's continued using the prior years 2/4 barrel cam. So in 71, but not 67-70, it would be accurate to talk about a "two barrel cam."

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