I have aluminum intakes on ALL of my carbureted engines and, knock on wood, have never had an issue. One went 360,000 miles after I bought the truck and installed the aluminum intake.
I did have the issue Jerry mentioned, but with an aluminum cylinder head (about 4 inches thick, rather than the 1/2~3/4 inch thickness of the intake mounting flange).
The different expansion rates not only compressed the gasket, but stretched the head bolts.
Jon