There was only one engine available to the SS427 buyer in 1967, the L-36 385 horsepower 427. The L-72 , which had been available on the Impala Super Sport in 1966, was in the midst of a one year absence from the full sized lineup. The strange thing is that in the 1967 full sized assembly manual, there are instructions concerning various aspects of the L-72 engine.

Also, according to Mr. Alan L. Colvin in his book "Chevrolet By The Numbers", there were 17 of the 425 horsepower L-72s installed in the big Chevrolets that year, probably through a special order. If that's true than it's very possible at least a few of them went into SS427 Impalas, which would make for an extremely valuable vehicle today. Since early 2005 two rumors have surfaced of claimed-to-be L-72 powered 1967 SS427 Impalas, but neither has been substantiated.

Also interesting is that there were apparently plans to include an optional tri-power configuration for the 1967 full sized vehicle. Known as RPO L-68, it was canceled before production began. This option is discussed more in detail in the 1967 exterior details section, in conjunction with the '67 SS427s special hood.

 
1967 L-36
1967 L-36
Shown above is the one of the finest examples of originality that I have ever seen under the hood of an SS427 Impala. This L-36 is from the blue sport coupe featured throughout the 1967 sections. Everything is about as correct as can be, right down to the proper color of window washer fluid!
First introduced in 1966, the L-36 was rated 385 horsepower@5200 r.p.m. for 1967. The EXACT same L-36 engine could be had optionally in the Corvette that year, yet it was rated at 390 horsepower. That kind of illustrates where the full sized Chevrolets were headed by 1967.
Car Life magazine did what has become a rather famous review of a 1967 Impala SS427 and gave the installed L-36 very high marks. In spite of a rather low axle ratio of 3.07:1 and Positraction, the guys from Car Life noted that "acceleration starts immediately" and that their biggest problem was "controlling rear wheel spin from a dead stop". When coupled to the optional M-20 4 speed transmission and 3.73:1 rear axle, the L-36 was sure to be a very capable street performer.

THE 1967 L-36 AS INSTALLED IN THE IMPALA SS427

Type
Cubic Inches
Horsepower
Block#
Main
V-8
427
385
38669942
2 bolt
V-8
427
385
33904351
2 bolt

The engine suffix codes pertaining to the 1967 L-36

Heavy duty three or 4 speed manual transmission, Super Sport only
IE
Turbohydramatic auto transmission, A.I.R*, Super Sport only
IF
Heavy duty three or 4 speed manual transmission, all except Super Sport
IH
Heavy duty three or 4 speed manual transmission, A.I.R. ,all except Super Sport
II
Turbohydramatic auto transmission
IJ
Turbohydramatic auto transmission, A.I.R., all except Super Sport
IO
Turbohydramatic auto transmission, Super Sport only
IS
Heavy duty three or 4 speed manual transmission, A.I.R. , Super Sport only
IX

* Air Injection Reactor

1967 L-72 assembly manual instructions

Pictured above is one of the sheets I mentioned earlier from the 1967 full sized assembly manual that actually does show the L-72 special high performance 427 engine. There is no "cancelled" to be found anywhere on any of the pages, but it is a well known fact that the L-72 was not an available engine to the 1967 full sized lineup. As I mentioned earlier, there were 17 of these monsters rumored to have been installed in big Chevys in 1967 and below are the engine suffix codes for such applications.

 

The engine suffixes codes pertaining to the mythical 1967 L-72 passenger car installations

Special high performance, 11 engines built, no record of installation
ID
Special high performance, 6 engines built, no record of installation
IK
All information provided through the exhaustive research of Mr. Alan L. Colvin in his book "Chevrolet by The Numbers: 1965-69".