Not sure if you mean why not use the OE sensor in the stock location, or with a front mount setup.
If you mean in the OE location, I have neither a Magnum block to mount one without buying an adapter, nor do I have a 134T flywheel with notches that is balance for my LA motor. I could buy both and spend $400 or more, but not only does it cost but I would have to pull the motor to install them.
If you mean, why not use the OE sensor in the front mount setup I have been working on, it's because the sensor is big and bulky. Pretty sure it is like 4" long or more. I think in the end it would make for a messy looking install.
