1966 Impala 327 - Impala Tech
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post #1 of 8 (permalink) Old 11-06-2010, 10:36 PM Thread Starter
 
 
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1966 Impala 327

I have the 4 door hardtop and have seen around online that there were a couple types of 327's put out that year with different HP. Was wondering how I could tell what one mine was. I do know that I have the 4 barrel carb but other than that not much more.
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post #2 of 8 (permalink) Old 11-06-2010, 11:31 PM
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They all came with a four barrel. Only the 283 came with a two barrel. Base horsepower was the 275 horse engine. There was also a 300 horse a 350 horse and a 375 horse variant. The two top engines had camel hump heads and mechanical valve tappets instead of hydraulic, the 375 was a Corvette only option and was fuel injected, and the 350 horse was equiped with a Holley. The two lower horse variants had a small triangle on top of the base rectangle called a Power Pack head and used a Rochester Quadrajet.

Big Dave
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post #3 of 8 (permalink) Old 11-06-2010, 11:51 PM
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According to my book (Chevrolet by the Numbers), only the 275 hp was offered in the full size passenger in '66.
If you look at the stamp pad on the front of the block, you should see one of these suffixes:

HAH - manual trans, Holley carb
HAR - manual trans, Rochester carb
HB - A.I.R. (air injection reactor)
HCH - Powerglide, Holley carb
HCR - Powerglide, Rochester carb
HF - Powerglide, A.I.R.
KE - Heavy Duty Clutch

1964 Impala 4 door sedan

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post #4 of 8 (permalink) Old 11-07-2010, 01:20 AM Thread Starter
 
 
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K thank you, just got this car a couple months ago and I am trying to learn as much as I can about it. another question I had was when it comes to gas I have been using regular and adding the lead additive to my fuel when I refuel. I have heard that you can do something to the heads on the engine so that you don't need to add lead substitute. How much does it cost on average to have that done to the stock heads and is it hard? Aslo could you swap out the heads for another year sbc head and not loose horsepower?
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post #5 of 8 (permalink) Old 11-07-2010, 09:51 AM
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Quote:
Originally Posted by Brandonion1985 View Post
K thank you, just got this car a couple months ago and I am trying to learn as much as I can about it. another question I had was when it comes to gas I have been using regular and adding the lead additive to my fuel when I refuel. I have heard that you can do something to the heads on the engine so that you don't need to add lead substitute. How much does it cost on average to have that done to the stock heads and is it hard? Aslo could you swap out the heads for another year sbc head and not loose horsepower?

You probably have enough lead build up in your motor now so that you can forgo adding the lead (which is highly carcinogenic) and just run high test (91-93 R+M Octane) in your motor. The base 275 horse 327 shipped with flat tops and a cast 64 cc combustion chamber for a 10.25:1 static compression ratio. You are probably running closer to 9.2:1 dynamic compression now which is within the limits of pump gas.

If you experience any detonation add one gallon of Toluene (lacquer paint thinner) to you full tank of gas to raise the octane (R+M) up to about 95 assuming you add one gallon of Toluene to 19 gallons of gasoline.

Newer heads all have hardened valve seats (cast iron is brittle but has a low Brinell hardness number of about 120-150 for gray cast iron so it is considered soft). A hardened valve seat is nearly ten times harder and will not erode the way the cast iron will. Any late model head except the Vortec heads made after 1996 will bolt up to your car and have hardened seats. Unfortunately it will also have larger 72 to 78 cc chambers to drop your static compression.

You get free horsepower with higher compression which is why all of the muscle cars of the late sixties required 100+ octane premium pump gas to run (Sunoco Blue 260 was rated at 104 octane which is considered to be racing gas today).

Big Dave
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post #6 of 8 (permalink) Old 11-07-2010, 10:07 AM
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You could also get your existing heads rebuilt with hardened seats. This is the routine thing to do with any valve job these days.

1964 Impala 4 door sedan

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post #7 of 8 (permalink) Old 11-07-2010, 10:46 AM
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JUst for the record

As stated, the full size chevrolet offered the 327/275 HP only. There were however 2 versions of the 283. 1 version was the base model 283/195 HP single exhaust and then the 283/220HP 4 BBL dual exhaust version. Both 283 versions offered only the flags on the front fenders, the 327 offered the flags with the 327 emblem above them.

Paul

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post #8 of 8 (permalink) Old 11-29-2012, 09:49 PM
 
 
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Quote:
Originally Posted by Big Dave View Post
They all came with a four barrel. Only the 283 came with a two barrel. Base horsepower was the 275 horse engine. There was also a 300 horse a 350 horse and a 375 horse variant. The two top engines had camel hump heads and mechanical valve tappets instead of hydraulic, the 375 was a Corvette only option and was fuel injected, and the 350 horse was equiped with a Holley. The two lower horse variants had a small triangle on top of the base rectangle called a Power Pack head and used a Rochester Quadrajet.

Big Dave
The 327 I put in my '57 has an cast date of B147 (3/17/67) and assy. date of 0306 (Mar 06). It came out of a wagon. It was the 275hp version, HF suffix, w/hyd lifters, a Q-jet, thin steel head gaskets, pistons w/valve reliefs and 462 camel hump heads, [and a cam w/3 flat lobes]. The cast dates on the heads and intake are all Feb '67.

Last edited by Speedi D; 11-29-2012 at 09:53 PM. Reason: Jus' tryin to get it all together!
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