Stock Hemi intake

Anybody have the casting numbers by year 66-71 thanks

All years have the same casting number but smaller details set them a part through the years

I agree! Still seem to read conflicting posts on the "P" stamping location/direction per year(s). Anyone know the final word?

Mine has the big pentastar in front?
Since I’m new to these intakes, why the difference on the front holes on back carb, I know the engine just runs off the back carb till you nail it.

The P size and location varies, generally speaking the smaller P started in 1968, went to the larger style sometime in 69 and remained through 71. Location and clocking varied, likely random. They do not run on just the primary exclusively, the front carb (secondary) also has an idle circuit criticle to proper fuel distribution. The front to rear intake port variable is typical of a dual plane intake design, it has to do with proper fuel distribution at various rpms the first design without the Pentastar was the 1966 and early 1967 design, the Pentastar was added early in the 67 model year.

I think he is talking about the holes in the manifold. Most tuning recommendation is to add some idle rpm on the front carb so that you are not purely on the back at idle. But it is true that the back is doing the heavy lifting, with a progressive linkage that will not operate the front carb linkage at idle and low throttle application. I imagine that notch is to ensure some balance coming out of the rear carb primary venturi's at idle and low rpm. But no expert on that, just a guess.

Thats exactly why the notch is there-

This is a small "P" example, I've seen these on 67's and 68'

Do the heat holes have to be blocked off or just left open (using headers)

You can leave them open, they both go into one large chamber in the manifold.