Product Information Hydraulic Roller - 4-Pattern .900" Base Circle: Recommended in highly modified 420+ c.l. stroker applications with raised compression. 3500+ stall.; Outboard Specs: 313/325 Advertised Duration, 260/270 Duration .050", .637"/.621" Lift, 110.5 Lobe Separation; Inboard Specs: 311/323 Advertised Duration, 258/268 Duration .050", .637"/.621" Lift, 109.5 Lobe Separation; 3200 to 7500 RPM range; Recommended use with 1.6 rocker arm ratio
