Use the ARP 899-7600 Piston Ring Compressor (3.760" Bore) for your engine build. This Piston Ring Compressor is a must-have in your shop! ARP's Ring Compressors are made to the specific bore on your engine and are far superior to other conventional tapered devices on the market. Each Piston Ring Compressor is CNC machined from from 6061-T6 billet aluminum tube material.