As I have stated before, 1969 is by far the easiest year of the Impala SS427 to fake. Not only because of the lack of distinguishing interior and exterior features, but also because of the abundance of 427 engines available in 1969. Along with the L-72 and L-36, a third variant of the 427 was available, the 335 horsepower mild performance LS-1. Any of these three engines could be had with a big Chevrolet. This means that there were a LOT of basic Impalas that were equipped with one of the 427s.

I have seen more 427 powered Impalas of the 1969 model year than any other. With reproduction emblems so easily acquired, it is commonplace now to go to a show and see phony 1969 SS427s. What has always amazed me is the frequency at which this happens. Out of the 2,455 SS427 Impalas that were made in 1969, there are only 5,245 remaining in existence today! (Sarcasm!)

What follows is an outline of the engines available to the 1969 SS427.

 
69 dealers form, additional options

Once again the L-72 was the top of the line engine available in the 1969 Impala SS427, and once again it was not even mentioned in the Chevrolet sales brochures. Accordingly, few buyers knew it was out there for the taking and only 546 were installed in all of the big Chevrolets. It's impossible to know how many were put into SS427 Impalas as Chevrolet did not keep that strict of records.

Take a look at the link above and to the right that shows the additional options section of the 1969 dealer's form. It specifies that the L-72 was to be used with the SS427 and that the dealer was to also check the Z-24 option box. I guess we all know how far that went, and the L-72 ended up in all the full-sized vehicles.

THE L-72 AS INSTALLED IN THE 1969 IMPALA SS427

Type
Cubic Inches
Horsepower
Block #
Main
V-8
427
425
3955270(early)
4 bolt
V-8
427
425
3963512(midyear)
4 bolt
V-8
427
425
3935439(early)
2 bolt

Chevrolet seemed to go crazy with the engine suffix codes in 1969. What follows is all of the suffix codes pertaining to the L-72.

Manual transmission
LD
Manual Transmission, heavy duty clutch
MD
Turbohydramatic automatic transmission
LS

 
Referred to as "The King" by the 1969 Chevrolet sales brochure, the L-36 was the most powerful cataloged engine available to the full-sized lineup. It garnered a 5 horsepower increase over the previous few years, now rated at 390bhp. This was due to some minor modifications of the pistons, heads and camshaft. Very little else was changed, and compression remained at 10:25:1. A very stout performer, this engine was the included engine with the SS427, but could also be had with any big Chevy in 1969. 5,582 full-sized Chevrolets received this powerhouse in 1969. In traditional Super Sport fashion, the SS427s received the chrome valve covers, oil filler cap and air cleaner assembly.

Both of the engines shown above are the L-36 390 horsepower 427s. The one on the left is in a 1969 Caprice automatic transmission vehicle and features the correct style L-36 style air cleaner assembly. On SS427 Impalas, the cleaner lid would be chrome. It is difficult these days to find an engine compartment so correctly detailed and so I have used these pictures of a Caprice L-36 instead of an SS427 Impala.

The engine shown to the far right is a manual transmission vehicle and again shows the correct style of air cleaner assembly for a 4-speed car. The main visible difference between these two assemblies being the "Auto-Thermac" heat riser hump on the snout of the automatic transmission assembly.

Notice how the air cleaner snorkel on these engines are facing more towards the battery. In the 1968 engine specifications page I mentioned that Chevrolet reworked the 1969 air cleaner assemblies in response to customer complaints about the amount of contaminants picked up through this snorkel on the 1968 models. This is an example of that modification, which attempted to place the snorkel in a position facing an area of the engine compartment less vulnerable to dust and grime.

THE L-36 AS INSTALLED IN THE 1969 IMPALA SS427

Type
Cubic Inches
Horsepower
Block#
Main
V-8
427
390
3955270 (early)
2 bolt
V-8
427
390
3963512 (midyear)
2 bolt
V-8
427
390
3935439(early)
2 bolt

The engine suffix codes pertaining to the 1969 L-36

3 or 4 speed manual transmission, high performance
LA
Turbo 400 automatic transmission, high performance
LC
Turbo 400 automatic transmission, high performance, police
LF
3 or 4 speed manual transmission, high performance, police
LG
3 or 4 speed manual transmission, high performance, Super Sport 427
LH
Turbo 400 automatic transmission, Super Sport 427
LI
Heavy duty clutch, police, high performance
LZ
3 or 4 speed manual transmission, high performance, heavy duty clutch
MB
Super Sport 427, heavy duty clutch
MC

1969 saw the introduction of a third 427 power plant, the LS-1 335 horsepower variant. This engine was a direct replacement of the L-35 325 horsepower 396, which was phased out of the full size Chevrolet lineup after 1968. The LS-1 was NOT an available engine with SS427 equipment, but I have included it because inevitably many of the original LS-1 cars in 1969 end up as clones.

A mild performer, it was a very workman-like engine that offered both power and streetability, and was available in all full-sized Chevrolets. The most popular of the 427s in 1969, the LS-1 was installed in 18,308 passenger Chevrolets. As was stated earlier, the LS-1 was not listed as an available engine for the 1969 SS427. However, it is not outside the realm of possibility that some of these engines found their way into SS427 Impalas in 1969. Anything seemed possible back then, so I included the LS-1 statistics on this page.

Notice in the image above the style of air cleaner lid; this elongated "neck" is correct for the LS-1. Notice the difference between this air cleaner lid and that of the L-36 which used more of a snub nosed style. Often times this can clue you in to whether or not you are looking at a 335 horsepower 427; assuming the original air cleaner is still with the vehicle!

Type
Cubic inches
Horsepower
Block#
Main
V-8
427
335
3955270 (early)
2 bolt
V-8
427
335
3963512 (midyear)
2 bolt
V-8
427
335
3935439(early)
2 bolt

The engine suffix codes pertaining to the 1969 LS-1

3 or 4 speed manual transmission
LB
Turbo 400 automatic transmission
LE
Turbo 400 automatic transmission, police
LJ
3 or 4 speed manual transmission, police
LK
3 or 4 speed manual transmission, police, heavy duty clutch
LY
3 or 4 speed manual transmission, heavy duty clutch
MA

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All information provided through the exhaustive research of Mr. Alan L. Colvin in his book "Chevrolet by The Numbers: 1965-69".

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