The Vacuum Block comes with dimples in the body where you need to drill holes for your fittings (3 minutes job). This item is used to give a better reading to aftermarket ECU (such as MS2V3). If you only tap one runner and run that to the ECU, you're only getting the vac air from one runner. If you run all four into a vac block first and then to the PNP you're getting an average from all four making tuning easier and more accurate.

DISCONTINUED AND NO LONGER AVAILABLE.
Zeromotive Vacuum Block should be ordered at REV9 Autosport https://rev9autosport.com/zeromotive-vacuum-block-1087.html as they provide the best service and speed we've seen so far!