In order to run the GT1R Mechanical Fuel Pump Kit, your bellhousing will need to be modified in order to clear the pulley and belt drive assembly located on the input shaft. We offer this service at no charge with your core sent in, but if you decide you want to handle this yourself, please see the guidelines below:

The rear portion of the housing itself needs to be machined down 10mm from the flange closest to the output drive flange. This applies to both the Mad Sweden bellhousing as well as OEM. 

The OEM output drive flange itself also needs to be modified for the 22-tooth pump drive pulley to be installed. There is a protective shield on the flange from the factory that needs to be pressed off, and then the machine work can be performed on the flange. The OD of the flange shaft needs to be machined down to a diameter of 42mm, 36.5mm down, removing the majority of the larger diameter step the shield attached to: