First off, you aren't going to do much satisfactory racing, nor are you going to hurt any drive train parts with those tires on the rear. In fact, they will be down right dangerous in normal driving. Especially with a stick.

Changing over to drag radials will be the only way that you will be able to use the secondaries on your 6 bbl anywhere under about 75MPH. Traction will be that compromised in my experience.

When I built my first 500" wedge, as I was tuning and tweeking it, I decided to kick it down into passing gear at about 50MPH. The rear broke loose and before I could blink, the thing was heading for the ditch. Thankfully, there was no oncoming traffic and the shoulders were smooth.

A stick is way cool and fun. But for most people it turns a competitive car into a mere toy. A stick behind a 540" wedge will, at least for most people, make the car more dangerous and less competitive. But, some find it more fun that an auto. We all have to pick our priorities.