She'll always do it, the question is how fast. You can always slow down, drop it a gear and keep the throttle just below your EGT limit... but you might be going 25mph in 2nd.
With a turbo and fueling, you can go a lot faster; cooling does become an issue, and it's one of those problems where if you slow down, you get less air flow, things get hotter, slow down, etc.
If you can find one, a Banks Sidewinder(wastegated) turbo is a really good match for a 'stock' 7.3 - one with a stock-sized(but maxed out) IP and no headstuds). Unplugging the wastegate on one will net you 14-16 psi, 200-220rwhp(about double N/A levels), which is pretty close to the maximum you want to run without studs, and also enough for the maxed stock IP.
R&D stage 1 injectors also seem to do well in this setup, but arem't required or anything.