Per The Aluminum Association, the typical Young's Modulus for the 70xx alloys is 10,400,000 psi and does not change based on the temper or heat treatment. The typical value for Young's Modulus varies from 10,000,000 to 10,600,000 depending on alloy with the higher strength alloys generally having the higher valuses. Curiously enough, The Aluminum Association does not list the Young's Modulus of 7xx alloys in their table of "Minimum Expected Mechanical Properties" in the 2000 version of their design manual. Perhaps someone out there has a newer version?