Double hump heads for 63 327
05-15-2013, 07:01 PM
#1
Drifting
Thread Starter
Double hump heads for 63 327
When I had a valve job done, the machine shop said these are the heads everyone wants. Really? What is so special about them? Are they the right thing for a 63 327?
05-15-2013, 07:54 PM
#2
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If the surface of the double-hump symbol on the heads in the photo are machined flat, they're correct Flint heads; if that surface is as-cast, they're Tonawanda non-Corvette heads. The casting date codes (under the valve covers) will also ID Flint vs. Tonawanda.
Last edited by JohnZ; 05-16-2013 at 04:18 PM. Reason: Added '64
05-15-2013, 08:02 PM
#3
Burning Brakes
Yes, they are the heads used on a 63 327 engine.
The phrase 'everyone wants' is a bit of a question. However, there are many after market heads that flow much better. If aluminum after market, runs with higher compression but less detonation.
Not particularly hard to find, I have two good sets in the corner of the garage (large valves with unshrouding cut).
Joe
The phrase 'everyone wants' is a bit of a question. However, there are many after market heads that flow much better. If aluminum after market, runs with higher compression but less detonation.
Not particularly hard to find, I have two good sets in the corner of the garage (large valves with unshrouding cut).
Joe
Last edited by devildog; 05-15-2013 at 08:05 PM.
05-15-2013, 10:43 PM
#5
Burning Brakes
Had a set FS on this forum and couldn't give them away. I am taking a set of 63's and a set of 65's along as a 62 BW T-10 to the scrap yard on Saturday unless anybody wants to buy them. Dave .
05-16-2013, 11:26 AM
#6
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05-16-2013, 12:44 PM
#7
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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.
Last edited by DZAUTO; 05-16-2013 at 06:34 PM.
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patg84 (10-12-2023)
05-16-2013, 01:14 PM
#9
Race Director
Interesting even though I don't have a SB engine.
Tom - fill us in sometime on the latest progress on the old Daisy Mae B-26.
Dan
Tom - fill us in sometime on the latest progress on the old Daisy Mae B-26.
Dan
05-16-2013, 01:33 PM
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Team Owner
DoZen Apples for the Teach
05-16-2013, 04:24 PM
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Great post, Tom, as always.
A-26 update?
A-26 update?
05-16-2013, 04:25 PM
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05-17-2013, 12:52 PM
#17
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Tom,
Just to add a tid-bit of info to your right-on explanation on these heads.
As a NHRA super stock racer since the 70's, the 461x head became the head to use because the NHRA listed the intake ports with a larger volume than the 461 or the 462. I think it was around 5cc bigger. Bigger ports means more power.
I even changed my 67 chevyII to a 66 so that I could use the x head.
Jim
Just to add a tid-bit of info to your right-on explanation on these heads.
As a NHRA super stock racer since the 70's, the 461x head became the head to use because the NHRA listed the intake ports with a larger volume than the 461 or the 462. I think it was around 5cc bigger. Bigger ports means more power.
I even changed my 67 chevyII to a 66 so that I could use the x head.
Jim
05-17-2013, 01:31 PM
#19
Advanced
Performance
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.
Wish I had looked more carefully at the valves when I put the heads on.
