Any small tips to help ET?

Sorry to re-open this thread, but I saw it was already recentley re-opened, haha. The comment about not shifting to third for the last half second or so, heres my question to the experts here... The crank was machined .10 when I rebuilt the motor a while back. It's a 77 360 with the cast iron crank. Whats the fasest I could push the car? What if it possibly went up to 6300-6500rpm? Would it be safe or risky? I hardly ever go over 6k. My dad stays at a modest 5500, haha. It would be nice to keep it in second all the way down the track if I get a good enough launch, but the last thing I want is a blown engine.