The smaller valve closed chamber head in 67 were 516's.
According to the books valve sizes on the 915 heads were 2.08 and 1.74 on the HP heads. Tell me where the 915 heads came from with 2.08 and 1.60 valves. I bought a set of 915's with the smaller valves and had 1.74's installed.
Factory Castings
Since the 1967-78 heads are the most readily available, and the most commonly used in street performance applications, we will limit our discussion to these heads. The year 1967 was significant for Mopar big-block heads with the introduction of the 915 casting, identified by the last three digits of the casting number. The 915 was a performance-minded redesign of the big-block head, featuring revised ports while retaining the closed-chamber configuration (typical factory chamber volume of 78.5 cc) of the earlier 1964-66 big-block heads. The 915 casting was found only on the 440ci big-blocks, as the 1967 383 engine retained the 516 castings of the previous year. In standard form, the 915 was fitted with 2.08-inch intake valves, and the same small 1.60-inch exhaust valves found in the older 516 heads. The year 1967 also was when the 440 Magnum engine was introduced. In step with the performance requirements of the Magnum, the engine’s exhaust valve size was increased to 1.74 inches, a size used successfully in some earlier high-performance packages.
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.
Read more:
http://www.moparmusclemagazine.com/techarticles/5115_cylinder_heads/index.html#ixzz1gqx1fC1l
