Plain Plug Gauge for ID in Jig Body Go 8.153 to 8.155 Cyl. 0.0001 Len. 35 to 36 with tapping of M4. NOGO 8.245 to 8.250 Cyl. 0.0001 Len. 10 to 11 / Std. Gauging area should have lapped finish. Gauge No. PPG 8200.8300