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Discussion Starter #1
Are the so called 'camel back' heads required/standard for the '66, 327 cu in, 275 hp engine? Stated another way, are the 'camel back' heads required for the engine to develop 275 hp?

Thanks
 

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Heads

If your asking if someone changes the stock configuration that was rated at 275hp with the heads, yes it will change. First it can go up or down depending on what you have or use in exchange. Secondly keep in mind that prior to 1972 HP was rated at Gross, then it changed to Net so to speak. What that means is your 275hp in 1972 terms is about 50hp less. Those heads were ok for their time, however even stock Vortec heads are better these days. That doesn't mean I would not use them though, just means that motor can go a whole lot more with todays help.

Jeff
 

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Discussion Starter #3
If your asking if someone changes the stock configuration that was rated at 275hp with the heads, yes it will change. First it can go up or down depending on what you have or use in exchange. Secondly keep in mind that prior to 1972 HP was rated at Gross, then it changed to Net so to speak. What that means is your 275hp in 1972 terms is about 50hp less. Those heads were ok for their time, however even stock Vortec heads are better these days. That doesn't mean I would not use them though, just means that motor can go a whole lot more with todays help.

Jeff
Jeff

Thanks for the reply.

My question may be better said as follows: I'm looking at a 327 with a suffix code of HCH which I believe is a '66 327 rated at 275 hp at the flywheel. When I look at the heads installed on this block, I do not see the 'camel backs'. Should I on a stock HCH 327?
 

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Heads

I am going to have to think about that. My first thought is yes, however it's mid 60's and things were changing HP wise, also even if the heads were camel heads, there was 2 valve sizes, 1.94 and 2.02, the 2.02 were the fuelies but that doesn't mean they weren't used on non fulie engines.

Jeff
 

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Discussion Starter #5
I am going to have to think about that. My first thought is yes, however it's mid 60's and things were changing HP wise, also even if the heads were camel heads, there was 2 valve sizes, 1.94 and 2.02, the 2.02 were the fuelies but that doesn't mean they weren't used on non fulie engines.

Jeff
Any help you can provide is greatly appreciated.

There are so many permutations I can't keep up with them all. I have not been able to find any info on what heads were stock on the '66 HCH suffix 327. I think '66 was the year there was only two versions of the 327; 275 hp and 350 hp, but I am not sure about that either.
 

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To answer your question, yes, a '66 327/275 will have the smaller "Fuelie Heads" with 1.94 Valves. They are also supposed to have the "Camel Back" or "Double Hump" markings, but....

The markings can be somewhat of a strange thing. Some of those heads actually have the Double Humps, but part of one Hump may be ground down. What do the markings look like on the Heads that are on the engine now?

It also would be a good idea to get the Casting Numbers as well as the Date Codes on them.

The 327/275 HCH is a real good engine. Are you familiar with what the last "H" stands for?

Bill
 

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Heads

Thanks for the help Bill, I don't claim to be versed on all engines and I was hoping you or someone would chime in with some help. Even with what I know, some things are becoming harder to remember, and others are just wrong facts that have been spread around for years. I had to laugh when I purchased my 4th 65 impala in September. I told my wife that you would think after owning 3 others I would know the car, however it's been since 86 that I owned my last 65, however that shold not be an excuse. I have owned all makes and models of cars from 1928 to 2007. I like cars and bikes, ( mostly harleys but have owned goldwings and BMW's too ) I was a master tech for harley also. I just like things that make me happy, don't care what it is though primarily GM.

Jeff
 

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Discussion Starter #8
To answer your question, yes, a '66 327/275 will have the smaller "Fuelie Heads" with 1.94 Valves. They are also supposed to have the "Camel Back" or "Double Hump" markings, but....

The markings can be somewhat of a strange thing. Some of those heads actually have the Double Humps, but part of one Hump may be ground down. What do the markings look like on the Heads that are on the engine now?

It also would be a good idea to get the Casting Numbers as well as the Date Codes on them.

The 327/275 HCH is a real good engine. Are you familiar with what the last "H" stands for?

Bill
Thanks for the reply.

I do not have the casting numbers but will try to get them.

The only 'markings' I saw were two small raised rectangles, side by side, in the approximate same location as the 'camel backs'.

Hypothetically, if these are the 'power packs' off an older 250 hp engine, what would be the overall affect? Reduced hp and torque? Anything else?

As I understand, the last H is for Holly carb. However, this engine has a quadrajet on an iron manifold and the 2" exhaust manifold. The car does have dual exhaust. The engine is install in a 1963 Impala conv. with a 4-speed manual (HCH is for a powerglide I believe).

Thanks again.
 

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Discussion Starter #9
Thanks for the reply.

I do not have the casting numbers but will try to get them.

The only 'markings' I saw were two small raised rectangles, side by side, in the approximate same location as the 'camel backs'.

Hypothetically, if these are the 'power packs' off an older 250 hp engine, what would be the overall affect? Reduced hp and torque? Anything else?

As I understand, the last H is for Holly carb. However, this engine has a quadrajet on an iron manifold and the 2" exhaust manifold. The car does have dual exhaust. The engine is install in a 1963 Impala conv. with a 4-speed manual (HCH is for a powerglide I believe).

Thanks again.
People,

Found the web site below and thought I would share. It seems to have all the info I need to ID my heads.


Head Casting By Year
 

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Looks like a pretty good site that you have found. By the markings, it sounds like you might have '68 327/250 Heads, unless they are some type of newer Heads. The Casting Numbers and Date Code will tell for sure.

Right, the last H is for a Holley Carb.

Bill
 

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I like cars and bikes, ( mostly harleys but have owned goldwings and BMW's too ) I was a master tech for harley also.
Jeff, I am also a Harley fan. I had a '72 XLH Sportster for over 8 years.

Also had a '74 XLCH for a while that I took in trade for a GMC truck I had for sale.

Bill
 

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Discussion Starter #12
Looks like a pretty good site that you have found. By the markings, it sounds like you might have '68 327/250 Heads, unless they are some type of newer Heads. The Casting Numbers and Date Code will tell for sure.

Right, the last H is for a Holley Carb.

Bill
That's my conclusion too. Thanks.
 

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Harley

That's cool Bill. I have had at least 15 harleys in my life from 1945 to 2002. Flatheads, sportsters, shovels, softails, springers, roadkings, and on. However I have a sweet spot for sportsters for some reason. They are really too small for me, but I had a 1966 900cc that I still cannot get over. I am also partial to flathead 45's.
 

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To answer your question, yes, a '66 327/275 will have the smaller "Fuelie Heads" with 1.94 Valves. They are also supposed to have the "Camel Back" or "Double Hump" markings, but....

The markings can be somewhat of a strange thing. Some of those heads actually have the Double Humps, but part of one Hump may be ground down. What do the markings look like on the Heads that are on the engine now?

It also would be a good idea to get the Casting Numbers as well as the Date Codes on them.

The 327/275 HCH is a real good engine. Are you familiar with what the last "H" stands for?

Bill

Correct me if I'm wrong here, As I'm stepping into the chevy world and learning. Isn't there two version of the double humps, one is a 1.94 and the other is a 2.02, The only way to tell is to pull the valve covers. look at the casting number and reference to it.
 

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Correct me if I'm wrong here, As I'm stepping into the chevy world and learning. Isn't there two version of the double humps, one is a 1.94 and the other is a 2.02, The only way to tell is to pull the valve covers. look at the casting number and reference to it.
That would be correct.

Bill
 

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What Size Holley Carb?

I have a 1966 327/275 camel hump head engine block with the engine code HCH. The last H stands for 4bbl Holley Carb. It currently has a Rochester 2jet on it and I am converting it back to the Holley 4bbl. My questions is, what is the correct size Holley carb? I have seen 600 cfm, 650 cfm etc. Does anyone know what size the stock Holley was?
 
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