Yes, it is a carry over from the days when the 427 L36 air cleaner had a different snorkel than the L35 396. Again it was a broader snorkel with greater cross section.

The LS1 had a milder cam, single exhaust system with a resonator, and generally tall gear ratios (2.56 with automatic). The tapered snorkel was designed to silence the intake noise. The broader snorkel on the L36 was less effective at complete intake silencing but was able to breather better at higher RPM or under heavier load.

Here's a good link comparing all the 427's for 1969. The air cleaner difference is mentioned.

http://www.impalass427.com/69engine.htm

CdnGMfan wrote:

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Yes, it is a carry over from the days when the 427 L36 air cleaner had a different snorkel than the L35 396. Again it was a broader snorkel with greater cross section.

The LS1 had a milder cam, single exhaust system with a resonator, and generally tall gear ratios (2.56 with automatic). The tapered snorkel was designed to silence the intake noise. The broader snorkel on the L36 was less effective at complete intake silencing but was able to breather better at higher RPM or under heavier load.

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 Surprisingly, according to factory documentation, both 427s and even the 2bbl 396 had identical gearing as standard equipment; 2.56 with auto and 3.31 with manual trans.

3.08s if you had the powerglide (which I guess would be smallblock only).  And a 350/250 with a powerglide and 3.08s was a legitimate ten second car.  To sixty, that is.