That said .7 seconds is a hell of a lot of time to shave off your 40 yard dash, especially if you're starting out in relatively decent shape. But I suppose the only way to know is to go for it, good luck!
And I agree, .7 seconds would be a feat by itself. Right now my best hope is to work on my flexibility and work hard at those drills. My flexibility is poor right now and definitely contributing to my slower time. When running I couldn't help but feel like I just wasn't able to move my legs as fast as they should. It was compounded by the fact that after 5 or so in a row I wasn't winded at all, which meant that my conditioning wasn't the problem.
But I'll go for it and hopefully this next 40 time is in the 4's.