"So when you spot violence, or bigotry, or intolerance or fear or just garden-variety hatred or ignorance, just look it in the eye and think... The good outnumber you, and we always will." Patton Oswalt
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
Same general idea as the 1970 345 hp LS4, and the 390 hp LS5. It all revolves around the valve train. Just a different cam, and pushrod size. Lower hp used low lift cam and 5/16" pushrods, higher hp used high lift cam and 3/8" pushrods. I presume the distributor may have a slightly different curve, and a different stamping on the carb, but the bones of it are the cam and pushrods.
I've got a low lift cam in the garage somewhere, it came out of my LS4 in 1980.