Chuck Melton
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I recently picked up a 440, speaking to the guy that I bought it from told me that 452 heads were possibly just as good as 906 heads, any imput would be appreciated...
440
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Here's a little info cribbed from Mopar Muscle
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.
While the 906 and its open-chamber configuration presented a small flow improvement over the previous year's 915, it was a step in the wrong direction in terms of performance. Racers in the know have long coveted the 915's closed-chamber heads, not for better flow, or even the higher compression offered by the closed chamber's smaller volume. The racers value the heads because of the superior combustion characteristics associated with the closed chambers. The 906, and all later heads that shared the same open-chamber configuration, did have an advantage in one area--lower emissions. The less intense burn and less effective scavenging resulted in reduced levels of nitrogen oxides (NOx). The 906 casting was retained as the B/RB head for 1969 to 1970 with no notable changes.
In 1971, a new casting was introduced--the 346, again used across the board on all big-blocks, B, and RB (although some early 1971s were reputed to have slipped through with the 906s). Although the 915 of 1967, and 906 of 1968 to 1970, had the same ports, the new 346 was a significant departure in terms of intake port configuration. Exhaust ports were essentially unchanged. Factory information on the 346 casting, as published in the old Direct Connection racing manuals, and carried over into today’s Mopar Performance engine book, was limited to one line: "In 1972 (and late 1971), the new emissions head with the flatter intake port was introduced on all ’B’ engines, and has a casting number of 3462345." Other than printing the wrong year and casting number, it was clear that this was a smog head to be avoided. No supporting information was provided, but in the minds of Mopar enthu-siasts, the written words have long been accepted as gospel. Interestingly, these same smog heads were the recommended heads for Grand National racing when the Wedge returned to NASCAR, and in modified form were used quite a bit by Richard Petty in his domination of the circuit in the early 1970s. The 346 head was retained as the standard big-block head through 1973.
From 1974 to the end of big-block production in 1978, several different castings were used--the 902 in 1974, the 975 in 1975, and the better-known 452 from 1976 to 1978. All these heads were minor variations on the 346 casting from 1971, with differences associated with durability details such as hardened valve seats, improved crack resistance, and an enlarged guide boss in the valve seal area. The intake port remained unchanged from the 1971 346 casting. The exhaust port was never significantly changed and remained true to the form introduced back in 1967 on the 915 heads. To sum up, two intake port configurations were used beginning in 1967 on big-block heads. The first was the 915 closed-chamber head and its successor, the 906 open chamber. The second intake port type was introduced in 1971 on the 346 open-chamber head. This port had a substantially lowered roof and greatly reduced short side, with a "Humber Hump" configuration on the cylinder wall-side floor. This port was carried through on the 902, 975, and the last of the production big-block heads--the 452, all of which were open-chamber designs. On the exhaust side, the 915, 906, 346, 902, 975, and 452 all featured the same basic port. As a result of the need to run unleaded fuel, retrofitting to the late 452 heads, with their induction-hardened valve seats, became a popular swap on earlier engines. Interestingly, the 452 gained a reputation as a desirable performance head casting; through experience, Mopar enthusiasts discovered the performance was on par to that of the esteemed 906 castings of the musclecar era. This regard did not return to the earlier 346 heads, even though the port configuration was virtually identical.
Read more: http://www.moparmusclemagazine.com/techarticles/5115_cylinder_heads/#ixzz2RCqJkF9y
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.
While the 906 and its open-chamber configuration presented a small flow improvement over the previous year's 915, it was a step in the wrong direction in terms of performance. Racers in the know have long coveted the 915's closed-chamber heads, not for better flow, or even the higher compression offered by the closed chamber's smaller volume. The racers value the heads because of the superior combustion characteristics associated with the closed chambers. The 906, and all later heads that shared the same open-chamber configuration, did have an advantage in one area--lower emissions. The less intense burn and less effective scavenging resulted in reduced levels of nitrogen oxides (NOx). The 906 casting was retained as the B/RB head for 1969 to 1970 with no notable changes.
In 1971, a new casting was introduced--the 346, again used across the board on all big-blocks, B, and RB (although some early 1971s were reputed to have slipped through with the 906s). Although the 915 of 1967, and 906 of 1968 to 1970, had the same ports, the new 346 was a significant departure in terms of intake port configuration. Exhaust ports were essentially unchanged. Factory information on the 346 casting, as published in the old Direct Connection racing manuals, and carried over into today’s Mopar Performance engine book, was limited to one line: "In 1972 (and late 1971), the new emissions head with the flatter intake port was introduced on all ’B’ engines, and has a casting number of 3462345." Other than printing the wrong year and casting number, it was clear that this was a smog head to be avoided. No supporting information was provided, but in the minds of Mopar enthu-siasts, the written words have long been accepted as gospel. Interestingly, these same smog heads were the recommended heads for Grand National racing when the Wedge returned to NASCAR, and in modified form were used quite a bit by Richard Petty in his domination of the circuit in the early 1970s. The 346 head was retained as the standard big-block head through 1973.
From 1974 to the end of big-block production in 1978, several different castings were used--the 902 in 1974, the 975 in 1975, and the better-known 452 from 1976 to 1978. All these heads were minor variations on the 346 casting from 1971, with differences associated with durability details such as hardened valve seats, improved crack resistance, and an enlarged guide boss in the valve seal area. The intake port remained unchanged from the 1971 346 casting. The exhaust port was never significantly changed and remained true to the form introduced back in 1967 on the 915 heads. To sum up, two intake port configurations were used beginning in 1967 on big-block heads. The first was the 915 closed-chamber head and its successor, the 906 open chamber. The second intake port type was introduced in 1971 on the 346 open-chamber head. This port had a substantially lowered roof and greatly reduced short side, with a "Humber Hump" configuration on the cylinder wall-side floor. This port was carried through on the 902, 975, and the last of the production big-block heads--the 452, all of which were open-chamber designs. On the exhaust side, the 915, 906, 346, 902, 975, and 452 all featured the same basic port. As a result of the need to run unleaded fuel, retrofitting to the late 452 heads, with their induction-hardened valve seats, became a popular swap on earlier engines. Interestingly, the 452 gained a reputation as a desirable performance head casting; through experience, Mopar enthusiasts discovered the performance was on par to that of the esteemed 906 castings of the musclecar era. This regard did not return to the earlier 346 heads, even though the port configuration was virtually identical.
Read more: http://www.moparmusclemagazine.com/techarticles/5115_cylinder_heads/#ixzz2RCqJkF9y
Hemi Rebel
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I'm using ported 346 heads with 2.14 in 1.81 ex valves for my 68 super bee
383man
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Yes 452's are just about the same as 906's. The 452's actually had hardened valve seats from the factory and flow about identical as the 906 heads. I used 452 heads a few times over the years as for an iron head they work fine but they are an open chamber head just like the 906. Ron
Chuck Melton
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Thanks, your info has been helpful
- - - Updated - - -
Think I'm gonna give them a try
- - - Updated - - -
Think I'm gonna give them a try
Seax440Dodge
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I don't know why people think what they do about 452's, easy to come by, flow just like a 906, hardened seats... but it seems like I can't walk through my garage without tripping on a set :eusa_eh:
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The 452's have larger water ports than the 906's for better cooling and alittle more durable.
67Satty
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I'm running 452s on the 440 in my Satellite. They have the stock-sized valves and are unported. They've done 7.86 in the 1/8 so far at a track with always bad DA. I think that would be in the 12.30 - 12.50 range in the 1/4. They seem to run out of steam between 5,000-5,500 rpm. If I want to go much quicker I'll probably have to get some aluminum heads. But for a street cruiser or something into the 12 second range at the strip, I think they do the job just fine.
383man
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Back around 2002 I had a very mild built 383 Dart I put together. You know RPM intake 750 DP and the MP .484 cam. Rest of the eng including the pistons were stock and I used 3.91's. And I used 452 heads on it that I did the valve job and some mild pocket porting (bowl blending) on them. Its best pass was a 12.31 @ 110 which was a 7.86 1/8 mile. I think the mph was about 88 mph. Funny though as it ran the same 1/8 as you did so you have an easy 12.30 car. Ron
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