In case there is any confusion, the E-Locker RSNAKE ia reffering to is an electric locking system which can be locked solid as a spool or unlocked to operate as a posi unit with the flip of a switch on the dash.

Weight wise, it was MUCH heavier than a spool, but I did not notice any power loss from the rotating assembly. I installed it after having the ladder bars fatigue and break from driving 18.5 tires with a spool on the street.

The ARB Locker I was refering to is a similar unit, only it requires an air supply to lock the unit, and is "open" when unlocked. They are more commonly used in 4x4 trucks for rock crawling.

The Detriot locker is a mechanical posi type unit and does not fully lock a rear end. There have been instances, particuarly in 4-speed cars, where the Detroit unit can create an unequal power distribution when power is first applied or between shifts. I ran one in a 383 4-speed car and every shift the car moved a few inches right before it locked again. Had an Automatic car with the same gears set (8-3/4) and it ran straight.

And if anyone can make a Detroit locker work, it would be Dr.Diff