Not sure if all LS's are CARB approved but 1975 is the cut off date. so if you install anything in a pre-1976 vehicle there is no smog check required so anything passes...
I had a friend that put a nasty small block in a late 80's(86 I think) 4x4 that was originally a diesel truck.... he never had to worry about getting in smogged since it was classified a diesel truck.....
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1956 Chevy Bel Air 2 door
1956 Chevy 210 4 Door
1970 K20 LWB project the Hulk build w/Supercharged 4.8L-ly2/4L60E
HULK BUILD
1970 C10 Yellow/White Deluxe LWB w/ 5.3L-LC9/6L80E
1968 K10 LWB Dark green my son calls it "THE HULK Jr"
HULK JR *SOLD*
GO
GO!!!