Sure-Grip or Not

I cannot make a decision if I would like a sure-grip differential or leave it open. 70 Swinger w/340 4 speed, mostly stock engine w/ Thermoquad carb and 71 cast iron manifold. I have a budget of around $500, and pretty much Dr. Diff has everything I would need to change it out. The car doesn't hit the track, but I don't see the point of leaving 90 foot long burnouts. LOL

I am going to keep the ring and pinion gears, (3.23) and its a 741 case with the stock axle bearings, not green. If I changed out the differential do I have to mess with pinion depth, or just adjust the back lash via adjusters?

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