PRP Torque Plate - Yamaha 1.8 SVHO Jetski Engines ALLYamaha 1. 8 SVHO engines (GP1800R, FZS, FZR, FX, jetskia) Our PRP torque plate is almost essential when boring and honing your block. Made from 6061 billet alloy especially designed and profiled to replicate head tensional dynamics. Its a fact that bores pull out if round when you torque your head down onto your block, more so if you run aftermarket bolts with more than OEM tension, you should be using a torque plate for boring AND honing, you should