Bought the plenum spacer kit to install my 5/16" MD spacer. Received the kit with the proper label and inspected all the bolts. For some reason there are eight 35mm and four 20mm that they want you to use along the outside of the plenum (bolts 10-18). These should all be 35mm. The four 20mm they supply are too short to even thread into the lower plenum even though 5/16" is almost half of the 10mm they say this kit will work with.