Quote:

How many CC's in a stock 906 chamber? What size are the valves? What size valves do people normally move up to if they have work done?



From Mopar Muscle Magazine:

"Over the years, confusion and mythology arose around the 915 casting, and it mistakenly became known as the 1967 440 Magnum head. This same head was also found on all 440s in 1967--from your old man’s 440 New Yorker to the boss’s 440 Imperial. The only difference was the smaller exhaust valve in the non-Magnum engines. A throat cut and the bigger exhaust valve evened the score. For 1968, the big-block cylinder head was modified again. The new 906 head was identical in port configuration to the previous year’s 915. However, the 906 was cast with open combustion chambers (typical factory volume 88 cc). Also, the smaller 1.60-inch exhaust valve, which had been fitted in standard engines, was discontinued. The 1.74-inch exhaust valve now was used in all B/RB heads. Despite the popular misconception that the 906 head was exclusive to the 440 Magnum and the new-for-1968 383 Magnum, it was actually used across the board, with the same valve sizes in all big-block engines for 1968. From the 383 two-barrel to the 440 Magnum, the heads were unchanged. Some of this confusion can be attributed to Chrysler’s advertising of the day, in which the 383 Magnum was heralded as "coming with the 440 Magnum’s free-breathing cylinder heads." What the mavens on Madison Avenue weren’t telling was that the standard 440, the 383 2V, and all passenger car big-blocks had the same 906 heads with the same valves--although the Hi-Po Magnums came with stiffer valve springs fitted. With the exception of some industrial, heavy truck, and motorhome application castings, this one-head-fits-all philosophy was carried through the end of big-block production in 1978."


Ya gotta pick through the Krapp that get posted carefully!!!