which is a better rearend what is the difference from the 4.12 to the 4.11 or the 4.86

A 4.86 will allow you to gear your car "deeper" to help you off of the corner on a short track; it's the gearsets that you use that'll make the big difference. Conversely. a 4.11 will allow you to achieve a higher top speed from the same RPM with the same gearset installed- it's probably more favorable if you run 3/8ths and 1/2 miles.

But it all depends on the gearset that you install..........