4-Pattern 253/263 IB, 255/265 OB Hydraulic Roller Cam for Ford 351W

Hydraulic Roller: 4-Pattern 305QIO8 - Recommended for larger c.i.d. and high compression applications. 3500+ Stall.*COMP Cams¨ 4-Pattern Camshafts are hydraulic rollers designed to optimize valve events based on runner length and feature a large increase in both area under the curve and stability at high RPMTo make the most power from your engine, you need to optimize the air ingested and captured by avoiding valves closing too soon or too late. Any conventional center layout single throttle body or carbureted V8 intake manifold features longer outboard runners and shorter inboard runners, meaning that each valve event should occur at a different moment.COMP Cams¨Ê4-Pattern Camshafts are the very first series of cams designed to accommodate this difference in length and avoid valves closing at the wrong times. NASCAR teams have been using camshafts designed this way for years, and using lessons learned along with them, COMP Cams¨Êhas designed a series of cams that optimizes valve events and features a large increase in both area under the curve and stability at high RPM.The camshafts feature four different lobe patterns with one intake and exhaust design for outboard runners, and another intake and exhaust design for the inboard runners. While the four inboard cylinders are all the same grinds, the outboard exhaust openings are two degrees earlier, with outboard intake closings coming two degrees later. This is the first ever use of technology in street vehicles to balance air/fuel ratio per cylinder and can net you a possible 1000+ RPM over other hydraulic rollers and anywhere from 5-20+ horsepower peak to peak, depending on cylinder head flow.The 4-Pattern hydraulic roller cams are CNC-Machined from steel billet cores with cast iron distributor drive gears. The cams also feature a tight lobe separation for both excellent performance and a throaty sound.*Upgraded valve train components and aftermarket cylinder heads required