Impala SS Help - Impala Tech
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post #1 of 11 (permalink) Old 02-16-2016, 06:33 PM Thread Starter
 
 
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Impala SS Help

Hi, I'm new to the blog, hoping to get some information. I'm looking at a 65 SS Impala to purchase and I have a few questions. This car is badged as a 427 turbojet, its a 4 speed with bucket seats. All the research that I have done say's Chevy only put a 396 in the 65 as a big block option besides the 409. Does anyone know if you could have ordered a 427 in this year. I know they made them, they were available in 63 as the Z11 option but not in 64 or 65 but then offered again in 66. Is it possible that this was a factory option? I would like to find the build sheet on the car, does anyone know where it might be located on the car? I have yet to run the numbers to find out if it's actually an SS, I will be looking at the VIN and the cowl tag this week and also looking to see if it has a 12 bolt rear end. I know it has a big block in it but until I run those numbers I wont know if it's a 396 or a 427. I very confused as to why someone would re-badge it as a 427 unless its a total clone, I will know more when I get some numbers, any help would be appreciated, thanks. Paul
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post #2 of 11 (permalink) Old 02-16-2016, 06:50 PM
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Right, the 427 wasn't available in the Impala till '66. With 427 Emblems on the side, it sounds like someone might have dropped one in it. Just get the Engine Suffix Code on the Front Pad on the Block and we will be able to tell you what you have.

Not all cars got Build Sheets, but the ones that did are usually under the Rear Seat.

Keep us posted on it.

Bill

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post #3 of 11 (permalink) Old 02-16-2016, 09:09 PM
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Welcome to the Team Paul!

The 396 was introduced in 1965 in November. GM's senior board couldn't make up there mind whether they wanted to use the 409's mystic (positive press with songs written about it) and build a 409 Mark IV engine (using the 409's bigger bore and shorter stroke, or go with the torque monster long stroke 396). The managers finally decided to go with the 396 (after building 150 409 versions for testing and evaluation) but because they procrastinated for so long the first six months production of the 396 block had very thick cylinder walls that could be over bored 0.381", which is more than a quarter inch) if you wanted to obtain a 0.060 over 409.

The 425 horsepower 427 was introduced in 1966 in the Corvette (there was a 390 horse version built for the full size B-body cars). The only way to obtain the 425 horse 427 in an Impala was to order it in a special edition car called the "427 SS Impala" (note that is not the same as an Impala SS with a 427 under the hood). It had a very special limited production blistered hood and F-41 suspension with Corvette disc brakes up front, just like you would get if you had ordered a Camaro SS, or a Chevelle SS. Everything on the 427 SS Impala was heavy duty.

Since the 427 didn't exist in 1965 it couldn't have been factory installed in the Impala that you are looking at. The ZL-1 427 you were talking about back in 1962 was a Mark I 409 block that had been stroked out to displace 427 cubes. It was a Mark II engine that was a prototype of the Mark IV 369/427/454 engine in that it used the newer head design with canted valves and a combustion chamber in the head instead of a flat head with he chamber in the piston like the earlier 409.

The Mark III was a still born wider bore centered block similar to what is currently run in the 500 cube Pro Stock Classes now. Chevy was looking at the costs of converting from the Mark I-Mark IV's 4.84-inch bore center to a bigger 5.00 inch center between the cylinder bores. This would have allowed for future growth on BBC displacements with a reasonable length stroke that would rev quickly (at the time Chevy was all about over square engines such as the 409, the 327, and the 427 and the 502; that all had a bore measured in inches that had a larger number than their stroke measurement).

Newer engines such as the 305 SBC and the LS-x engines are all under square where the bore is smaller than the stroke is long the same way Pontiac and Oldsmobile engines where built back in the day. Because this new BBC engine would cost a LOT in new tooling at the Tonawanda, NY foundry. This is why GM cancelled the project; though there where over five hundred blocks cast for engineering evaluation.

So the 348 and 409 are Mark I engines; the ZL-1 427 "Mystery engine" was a Mark II, the Mark III was still born leaving the 1965-1990 Mark IV series as what most are familiar with when you say big block Chevy. The newer Gen V and Gen VI blocks have a one piece rear main seal, and all Gen V, Gen VI blocks are four bolt main blocks with the Gen VI using a hydraulic cam. The Gen V can be distinguished from the Gen VI by a lack of a mechanical fuel pump boss on the front of the block (since they were all EFI, they didn't need a fuel pump driven off the cam and since they where installed in front of an automatic there is no clutch ball boss to use a mechanical clutch linkage)

Big Dave.

Last edited by Big Dave; 02-17-2016 at 08:42 AM. Reason: Inacurate date given
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post #4 of 11 (permalink) Old 02-17-2016, 12:00 AM
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Quote:
Originally Posted by Big Dave View Post

The 425 horsepower 427 was introduced in 1967 in the Corvette (there was a 390 horse version built for the full size B-body cars).

Since the 427 didn't exist in 1966

Big Dave.
Dave, you better check the book or website where you got that info from because they don't have it right. 66 Impala had an optional L72 427 available.

And just for kicks, here's a one-of-2 L72 66 Impala wagon proven to be authentic.


http://www.thetruthaboutcars.com/201...2-4spd-wagons/
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post #5 of 11 (permalink) Old 02-17-2016, 01:09 AM
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Also Big Block Engines for '65 was a split year. The 409 was available for the first part of the year and the 396 for the last part. I believe the Month for the switch was February of '65.

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post #6 of 11 (permalink) Old 02-17-2016, 01:13 AM
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Quote:
Originally Posted by Darth View Post

And just for kicks, here's a one-of-2 L72 66 Impala wagon proven to be authentic.

http://www.thetruthaboutcars.com/201...2-4spd-wagons/

That is an interesting '66 427 Wagon.

A friend of mine owns 2 original '66 427 cars. One being a Caprice.

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post #7 of 11 (permalink) Old 02-17-2016, 08:02 AM Thread Starter
 
 
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I was thinking perhaps it could have been dealer installed, if it was a late model year car. Hopefully I will be able to run some numbers tonight to get some closure. I will update as soon as I can with my findings, thank you everybody for the info.
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post #8 of 11 (permalink) Old 02-17-2016, 08:17 AM
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L72 Wagon

Just for the record there were 3 L72 15445 Wagons......


Paul

Paul

1966 Impala SS

Please Visit our new site:
http://www.winvoices.com/
1959 through 1988* window stickers, car shippers, dealer invoices, retail sales orders and tank stickers, expertly reproduced, for most Chevrolet Models.





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post #9 of 11 (permalink) Old 02-17-2016, 08:41 AM
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Sorry! Carl you are correct. The 396 came out in 1965 and the 427 appeared for the first time the following year in 1966.

Another case of old timers disease. Got confused. Aside from slipping the year everything else was correct. In 1967 the production big block had a major revision to the earlier Mark I oiling system so that it no longer used a grooved rear cam bearing that required you to line up five different oil holes to feed the top end with oil. The Mark IV block has much more metal in the main webbing than the Mark I did as that was a major weak point (the other was the rod bolt often failed due to the very heavy piston). Otherwise parts are almost directly interchangeable. You can install a 4.00" inch stroke 454 crankshaft in a 409 block (creating a 481 cube motor) if you first turn it down to the smaller main journal size used in the 409, but they share the same size rods.

Big Dave
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post #10 of 11 (permalink) Old 02-18-2016, 01:15 AM
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Quote:
Originally Posted by fsc66 View Post
Just for the record there were 3 L72 15445 Wagons......


Paul
Oh rats, I'll have to break the news to him...!!! Just kidding, I've seen most of his other cars but I still haven't made the days drive to his place to see this wagon. What a cool car....

He has a very cool L72 SS convert as well.
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post #11 of 11 (permalink) Old 02-18-2016, 10:23 PM Thread Starter
 
 
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Here will be my final post on this particular car. After a few attempts to actually see this "barn find" I actually got to see it and get some numbers. It is an actual SS Impala Big Block 4 speed but that's where all the good ends. Not the original motor, carbled up interior, rotted frame.......and the kicker!! he wanted 15,000.00 for it. I was very upset that the car was more than likely going to sit there until the roof comes down around it but you can't save them all. I will stick with my 61 Belair and finish it.....anybody have a line on some front fenders?...thanks for all the help
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