Double hump heads for 63 327
05-17-2013, 05:52 PM
#21
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Was/is there a noticeable performance increase with the 2.02 versus the 1.94 valve heads. It would seem there would be. I have a 1963 340shp solid lifter car and assume from your description it being pre 1964 would have the 1.94 valves?
Wish I had looked more carefully at the valves when I put the heads on.
Wish I had looked more carefully at the valves when I put the heads on.
Although, I have promised myself that my next personal engine is going to get a roller cam.
My point is, I cannot honestly objectively answer you question. BUT, I will say this, the two primary differences between a 63 340hp engine and a 64-65 365hp engine (and same for 360vs 375hp FI engines) is the 30-30 cam(64-65) vs the 097 cam(57-63) and the bigger 2.02/1.6 valves on 64-later engines. Of course, the 63 engines had an AFB vs a Holley on 64-later engines.
Sooooooooooooo, if a person had a 340hp engine (or 360FI), it would be EXPECTED that a noticeable increase would occur simply with the swap to a 30-30 and 2.02 heads.
Ya, ya, ya, ya, ya, I know, there will be a difference between the AFB and Holley and the advance curve between the 2 distributors, but as I said, the PRIMARY difference will be cam/heads.
Last edited by DZAUTO; 05-17-2013 at 05:57 PM.
05-17-2013, 08:06 PM
#22
In early 1965 I bought a set of brand new large valve 461's from Southview Chevy in So. St. Paul, Mn. for $150. I put them on a 327 in a 57 Chevy along with the 097 cam, 300 hp intake and a 500 cfm AFB. Had a 3 speed on the tree and 4.56 rear gears and was pretty quick!
05-17-2013, 08:12 PM
#23
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Maybe Tom can confirm this, but I thought the 61-63 461X heads had larger runners ( by 10cc's or so), even though they came with the smaller valves. I thought that was why the "X"heads were more sought after than the regular 461's, even though they had larger valves.
Bill
Bill
05-18-2013, 02:23 AM
#24
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Maybe Tom can confirm this, but I thought the 61-63 461X heads had larger runners ( by 10cc's or so), even though they came with the smaller valves. I thought that was why the "X"heads were more sought after than the regular 461's, even though they had larger valves.
Bill
Bill
Last edited by DZAUTO; 05-18-2013 at 02:27 AM.
05-19-2013, 01:35 PM
#27
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05-19-2013, 04:39 PM
#28
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Tom - fill us in sometime on the latest progress on the old Daisy Mae B-26. 
Dan[/QUOTE]Ditto. Are you going to put on wing tanks or are they on?
Doesn't the "X" mean a higher nickel content in the cast iron?
Dan[/QUOTE]Ditto. Are you going to put on wing tanks or are they on?
Doesn't the "X" mean a higher nickel content in the cast iron?
05-19-2013, 06:41 PM
#29
Le Mans Master
At the risk of being criticized and ridiculed, AGAIN, (I'm sick of it!!!!), I'll step in here and add some comments for better clarification.
The heads with the double hump symbols on each end, first appeared in 1961 on the Fuel Injected Corvette engines ONLY--------------nothing else. Thus, the origin of the term "fuelie heads". This same head was used through 1963. These were the 461 X heads. The X (contrary to frequent belief) DID NOT follow the casting number. The X was on the UNDERSIDE of the head near the intake surface.
ALL 461X (1961-63) ONLY came with 1.94/1.5 valves. In 1962 the 461X head was used on all optional (327) engines, BOTH Vettes and pass cars. Only the base 327 engine (250hp) still had the pyramid symbols.
The 461 head (NO X) was introduced in 64. There were some minor casting changes made to it including a slight change to the combustion chamber. The 64-66 461 heads came in BOTH 1.94/1.5-2.02/1.6 versions. The raw castings were the same, the difference was in machining for valves and unshrouding of the chamber wall around the intake valve if the head received 2.02 valves. The solid lifter engines (as well as the 350hp hyd cam) got the 2.02 heads, all others got the 1.94 version.
Below is a before and after comparrison of 461X/461 heads that have been opened up for 2.02/1.6 valves and unshrouding of the chamber wall. This unshrouding was done by the factory for 2.02 heads and ANY good machine shop that is familiar with these heads can do the same (as done below).
Sometime in mid-late 66, the 462 replaced the 461 head. In 68 the 291 and 292 heads replaced the 462 head, but the most distinguishing difference was the boss/hole for the temperature sending unit between #1 and #3 exhaust ports. This was a one year configuration. That is, the ends of the head were plain with only the double hump symbols AND the hole on the side for the temp sender.
ALLLLLLLLL of these double hump heads (461X, 461, 462, 291, 292) are virutally the same with very little differences.
Then in 69, due to changes in the accessories bolted to the engine, a very noticeable change was made to the ends of the heads. Additional bosses were cast for threaded holes to mount accessories such as AC, alternator, PS, etc. The chambers and ports of 69-70 double hump heads were basically unchanged. The next big change was in 71 with chambers significantly increased to around 76cc for lower compression.
ALL of the 61-68 double hump heads---------------PROVIDED THEY ARE IN GOOD, REBUILDABLE CONDITION WITH NO CRACKS----------------are, or can be made into excellent heads. It can be quite costly, and can even cost more to upgrade old double hump heads rather than to buy much better aftermarket heads. BUT ALLLLLLLLLLLLLLL aftermarket heads will have the flat, machined surfaces on each end with threaded holes. And for the person wanting the "plain" look of the earlier double hump heads, then the best option is to spend the money having them upgraded.
Except for my 70 Chevelle with a SB400, all of my other engines have early double hump heads with plain ends that have been re-worked and larger stainless valves added along with guide plates and screw-in studs.
For moderate performance, I also add roller TIP rocker arms (I see no benefit spending extra money for full roller rockers on a 5000-6000rpm engine).
One of the best, and more "modern" upgrades that can be done is to go with a retro roller cam/lifters which are readily availabe for the older engines.
The heads with the double hump symbols on each end, first appeared in 1961 on the Fuel Injected Corvette engines ONLY--------------nothing else. Thus, the origin of the term "fuelie heads". This same head was used through 1963. These were the 461 X heads. The X (contrary to frequent belief) DID NOT follow the casting number. The X was on the UNDERSIDE of the head near the intake surface.
ALL 461X (1961-63) ONLY came with 1.94/1.5 valves. In 1962 the 461X head was used on all optional (327) engines, BOTH Vettes and pass cars. Only the base 327 engine (250hp) still had the pyramid symbols.
The 461 head (NO X) was introduced in 64. There were some minor casting changes made to it including a slight change to the combustion chamber. The 64-66 461 heads came in BOTH 1.94/1.5-2.02/1.6 versions. The raw castings were the same, the difference was in machining for valves and unshrouding of the chamber wall around the intake valve if the head received 2.02 valves. The solid lifter engines (as well as the 350hp hyd cam) got the 2.02 heads, all others got the 1.94 version.
Below is a before and after comparrison of 461X/461 heads that have been opened up for 2.02/1.6 valves and unshrouding of the chamber wall. This unshrouding was done by the factory for 2.02 heads and ANY good machine shop that is familiar with these heads can do the same (as done below).
Sometime in mid-late 66, the 462 replaced the 461 head. In 68 the 291 and 292 heads replaced the 462 head, but the most distinguishing difference was the boss/hole for the temperature sending unit between #1 and #3 exhaust ports. This was a one year configuration. That is, the ends of the head were plain with only the double hump symbols AND the hole on the side for the temp sender.
ALLLLLLLLL of these double hump heads (461X, 461, 462, 291, 292) are virutally the same with very little differences.
Then in 69, due to changes in the accessories bolted to the engine, a very noticeable change was made to the ends of the heads. Additional bosses were cast for threaded holes to mount accessories such as AC, alternator, PS, etc. The chambers and ports of 69-70 double hump heads were basically unchanged. The next big change was in 71 with chambers significantly increased to around 76cc for lower compression.
ALL of the 61-68 double hump heads---------------PROVIDED THEY ARE IN GOOD, REBUILDABLE CONDITION WITH NO CRACKS----------------are, or can be made into excellent heads. It can be quite costly, and can even cost more to upgrade old double hump heads rather than to buy much better aftermarket heads. BUT ALLLLLLLLLLLLLLL aftermarket heads will have the flat, machined surfaces on each end with threaded holes. And for the person wanting the "plain" look of the earlier double hump heads, then the best option is to spend the money having them upgraded.
Except for my 70 Chevelle with a SB400, all of my other engines have early double hump heads with plain ends that have been re-worked and larger stainless valves added along with guide plates and screw-in studs.
For moderate performance, I also add roller TIP rocker arms (I see no benefit spending extra money for full roller rockers on a 5000-6000rpm engine).
One of the best, and more "modern" upgrades that can be done is to go with a retro roller cam/lifters which are readily availabe for the older engines.
I also matched the ports to exhaust and intake manifolds.And had a pro do a pocket port job.
Last edited by MiguelsC2; 05-19-2013 at 06:44 PM.
05-19-2013, 07:39 PM
#30
Burning Brakes
Hard to tell from the photos, but the casting symbol surface doesn't appear to have been machined - looks like an as-cast surface; photo below shows a machined and painted Flint head. Pop the valve covers off and look at the casting date format - if they have two digits for the year, they're Tonawanda heads with small (1.94") valves (Tonawanda never made 461/462/291/186 heads with 2.02" valves).
05-19-2013, 09:24 PM
#31
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The other way to read it would be May 2, 2003 if it was a Tonawanda casting, but those heads were only cast in the 1960's.
05-19-2013, 09:54 PM
#33
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05-19-2013, 10:02 PM
#34
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WHY???
Because they were in a 1963 model car, which could have ONLY been a Vette or full size car. Those were the ONLY two Chevy cars to have had a 327 in 63. Additionally, the 61-63 double hump heads ONLY came with 1.94/1.5 valves. As I mentioned above (if anyone read it), 61-63 double hump heads DID NOT, repeat, DID NOT get 2.02/1.6 valves until the 64 models.
For 63 model Corvettes, the double hump heads came on 300, 340, 360hp engines. But in the full size cars for 63, the ONLY optional 327 was the 300hp version. Of over 20,000 63 Corvettes built, 17,621 had optional engines with the double hump heads. BUUUUUUUUUT, in the full size cars, there were MANY thousand 300hp/327 engines installed. SOOOOOOOOOO, there is a somewhat higher percentage of 63 double hump heads that came from pass cars than from 63 Vettes. Of the 1963 pass cars that came with Tonawanda vs Flint engines with double hump heads, I have no clue. Since your heads are Flint heads, then the chances of them being from a Vette vs pass car is even greater.
Last, it makes absolutely NO DIFFERENCE if the heads were on a pass car or Vette engine------------THEY WILL BE EXACTLY THE SAME!
Last edited by DZAUTO; 05-19-2013 at 10:06 PM.
05-19-2013, 11:56 PM
#35
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Since they were cast in May 63, then it is EXTREMELY PROBABLE they are the 461X version. And if that is so, then they would only have had 1.94/1.5 valves.
WHY???
Because they were in a 1963 model car, which could have ONLY been a Vette or full size car. Those were the ONLY two Chevy cars to have had a 327 in 63. Additionally, the 61-63 double hump heads ONLY came with 1.94/1.5 valves. As I mentioned above (if anyone read it), 61-63 double hump heads DID NOT, repeat, DID NOT get 2.02/1.6 valves until the 64 models.
For 63 model Corvettes, the double hump heads came on 300, 340, 360hp engines. But in the full size cars for 63, the ONLY optional 327 was the 300hp version. Of over 20,000 63 Corvettes built, 17,621 had optional engines with the double hump heads. BUUUUUUUUUT, in the full size cars, there were MANY thousand 300hp/327 engines installed. SOOOOOOOOOO, there is a somewhat higher percentage of 63 double hump heads that came from pass cars than from 63 Vettes. Of the 1963 pass cars that came with Tonawanda vs Flint engines with double hump heads, I have no clue. Since your heads are Flint heads, then the chances of them being from a Vette vs pass car is even greater.
Last, it makes absolutely NO DIFFERENCE if the heads were on a pass car or Vette engine------------THEY WILL BE EXACTLY THE SAME!
WHY???
Because they were in a 1963 model car, which could have ONLY been a Vette or full size car. Those were the ONLY two Chevy cars to have had a 327 in 63. Additionally, the 61-63 double hump heads ONLY came with 1.94/1.5 valves. As I mentioned above (if anyone read it), 61-63 double hump heads DID NOT, repeat, DID NOT get 2.02/1.6 valves until the 64 models.
For 63 model Corvettes, the double hump heads came on 300, 340, 360hp engines. But in the full size cars for 63, the ONLY optional 327 was the 300hp version. Of over 20,000 63 Corvettes built, 17,621 had optional engines with the double hump heads. BUUUUUUUUUT, in the full size cars, there were MANY thousand 300hp/327 engines installed. SOOOOOOOOOO, there is a somewhat higher percentage of 63 double hump heads that came from pass cars than from 63 Vettes. Of the 1963 pass cars that came with Tonawanda vs Flint engines with double hump heads, I have no clue. Since your heads are Flint heads, then the chances of them being from a Vette vs pass car is even greater.
Last, it makes absolutely NO DIFFERENCE if the heads were on a pass car or Vette engine------------THEY WILL BE EXACTLY THE SAME!
05-20-2013, 01:48 AM
#36
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I see the next question coming. I DO NOT have the answer.
What did the X designate? Like I said, don't know. But most probably John Hinkley knows.
The X was used on several different castings, such as the early 461 heads, some 58-59 heads (they had X58) and there were some 409 blocks that had the X. I've heard various explanations about the meaning of the X, but I've never seen any GM documentation explaining the meaning of the X. Like I said, John Hinkley probably knows.
What did the X designate? Like I said, don't know. But most probably John Hinkley knows.
The X was used on several different castings, such as the early 461 heads, some 58-59 heads (they had X58) and there were some 409 blocks that had the X. I've heard various explanations about the meaning of the X, but I've never seen any GM documentation explaining the meaning of the X. Like I said, John Hinkley probably knows.
05-20-2013, 05:55 PM
#39
Drifting
I see the next question coming. I DO NOT have the answer.
What did the X designate? Like I said, don't know. But most probably John Hinkley knows.
The X was used on several different castings, such as the early 461 heads, some 58-59 heads (they had X58) and there were some 409 blocks that had the X. I've heard various explanations about the meaning of the X, but I've never seen any GM documentation explaining the meaning of the X. Like I said, John Hinkley probably knows.
What did the X designate? Like I said, don't know. But most probably John Hinkley knows.
The X was used on several different castings, such as the early 461 heads, some 58-59 heads (they had X58) and there were some 409 blocks that had the X. I've heard various explanations about the meaning of the X, but I've never seen any GM documentation explaining the meaning of the X. Like I said, John Hinkley probably knows.
I don't have any GM printed info to explain it, but from my experience (especially with "W" motor blocks), it would appear that the X signified a change to the mold but not enough of one to warrant a different casting number. For what it's worth, that is my deduction based on what I've seen. I have no information regarding the "X" on SB heads, but once a practice is established, I'd expect it to carry over to all castings. (or at least, most)
Verne
05-20-2013, 07:23 PM
#40
Team Owner
You dared us to criticize!
At the risk of being criticized and ridiculed, AGAIN, (I'm sick of it!!!!), I'll step in here and add some comments for better clarification.
The heads with the double hump symbols on each end, first appeared in 1961 on the Fuel Injected Corvette engines ONLY--------------nothing else. Thus, the origin of the term "fuelie heads". This same head was used through 1963. These were the 461 X heads. The X (contrary to frequent belief) DID NOT follow the casting number. The X was on the UNDERSIDE of the head near the intake surface.
ALL 461X (1961-63) ONLY came with 1.94/1.5 valves. In 1962 the 461X head was used on all optional (327) engines, BOTH Vettes and pass cars. Only the base 327 engine (250hp) still had the pyramid symbols.
The 461 head (NO X) was introduced in 64. There were some minor casting changes made to it including a slight change to the combustion chamber. The 64-66 461 heads came in BOTH 1.94/1.5-2.02/1.6 versions. The raw castings were the same, the difference was in machining for valves and unshrouding of the chamber wall around the intake valve if the head received 2.02 valves. The solid lifter engines (as well as the 350hp hyd cam) got the 2.02 heads, all others got the 1.94 version.
Below is a before and after comparrison of 461X/461 heads that have been opened up for 2.02/1.6 valves and unshrouding of the chamber wall. This unshrouding was done by the factory for 2.02 heads and ANY good machine shop that is familiar with these heads can do the same (as done below).
Sometime in mid-late 66, the 462 replaced the 461 head. In 68 the 291 and 292 heads replaced the 462 head, but the most distinguishing difference was the boss/hole for the temperature sending unit between #1 and #3 exhaust ports. This was a one year configuration. That is, the ends of the head were plain with only the double hump symbols AND the hole on the side for the temp sender.
ALLLLLLLLL of these double hump heads (461X, 461, 462, 291, 292) are virutally the same with very little differences.
Then in 69, due to changes in the accessories bolted to the engine, a very noticeable change was made to the ends of the heads. Additional bosses were cast for threaded holes to mount accessories such as AC, alternator, PS, etc. The chambers and ports of 69-70 double hump heads were basically unchanged. The next big change was in 71 with chambers significantly increased to around 76cc for lower compression.
ALL of the 61-68 double hump heads---------------PROVIDED THEY ARE IN GOOD, REBUILDABLE CONDITION WITH NO CRACKS----------------are, or can be made into excellent heads. It can be quite costly, and can even cost more to upgrade old double hump heads rather than to buy much better aftermarket heads. BUT ALLLLLLLLLLLLLLL aftermarket heads will have the flat, machined surfaces on each end with threaded holes. And for the person wanting the "plain" look of the earlier double hump heads, then the best option is to spend the money having them upgraded.
Except for my 70 Chevelle with a SB400, all of my other engines have early double hump heads with plain ends that have been re-worked and larger stainless valves added along with guide plates and screw-in studs.
For moderate performance, I also add roller TIP rocker arms (I see no benefit spending extra money for full roller rockers on a 5000-6000rpm engine).
One of the best, and more "modern" upgrades that can be done is to go with a retro roller cam/lifters which are readily availabe for the older engines.
The heads with the double hump symbols on each end, first appeared in 1961 on the Fuel Injected Corvette engines ONLY--------------nothing else. Thus, the origin of the term "fuelie heads". This same head was used through 1963. These were the 461 X heads. The X (contrary to frequent belief) DID NOT follow the casting number. The X was on the UNDERSIDE of the head near the intake surface.
ALL 461X (1961-63) ONLY came with 1.94/1.5 valves. In 1962 the 461X head was used on all optional (327) engines, BOTH Vettes and pass cars. Only the base 327 engine (250hp) still had the pyramid symbols.
The 461 head (NO X) was introduced in 64. There were some minor casting changes made to it including a slight change to the combustion chamber. The 64-66 461 heads came in BOTH 1.94/1.5-2.02/1.6 versions. The raw castings were the same, the difference was in machining for valves and unshrouding of the chamber wall around the intake valve if the head received 2.02 valves. The solid lifter engines (as well as the 350hp hyd cam) got the 2.02 heads, all others got the 1.94 version.
Below is a before and after comparrison of 461X/461 heads that have been opened up for 2.02/1.6 valves and unshrouding of the chamber wall. This unshrouding was done by the factory for 2.02 heads and ANY good machine shop that is familiar with these heads can do the same (as done below).
Sometime in mid-late 66, the 462 replaced the 461 head. In 68 the 291 and 292 heads replaced the 462 head, but the most distinguishing difference was the boss/hole for the temperature sending unit between #1 and #3 exhaust ports. This was a one year configuration. That is, the ends of the head were plain with only the double hump symbols AND the hole on the side for the temp sender.
ALLLLLLLLL of these double hump heads (461X, 461, 462, 291, 292) are virutally the same with very little differences.
Then in 69, due to changes in the accessories bolted to the engine, a very noticeable change was made to the ends of the heads. Additional bosses were cast for threaded holes to mount accessories such as AC, alternator, PS, etc. The chambers and ports of 69-70 double hump heads were basically unchanged. The next big change was in 71 with chambers significantly increased to around 76cc for lower compression.
ALL of the 61-68 double hump heads---------------PROVIDED THEY ARE IN GOOD, REBUILDABLE CONDITION WITH NO CRACKS----------------are, or can be made into excellent heads. It can be quite costly, and can even cost more to upgrade old double hump heads rather than to buy much better aftermarket heads. BUT ALLLLLLLLLLLLLLL aftermarket heads will have the flat, machined surfaces on each end with threaded holes. And for the person wanting the "plain" look of the earlier double hump heads, then the best option is to spend the money having them upgraded.
Except for my 70 Chevelle with a SB400, all of my other engines have early double hump heads with plain ends that have been re-worked and larger stainless valves added along with guide plates and screw-in studs.
For moderate performance, I also add roller TIP rocker arms (I see no benefit spending extra money for full roller rockers on a 5000-6000rpm engine).
One of the best, and more "modern" upgrades that can be done is to go with a retro roller cam/lifters which are readily availabe for the older engines.
You left him having to still figure it out from reading what you wrote.
Luckily, he seems like a smart guy and will get it. I just had to give you a hard time, because you dared us and your post was so good!
