You will need adjustable rockers with that cam. you can use stamp steel but performance will not be at its peak. Larger cams do not have larger lobes they have a smaller base circle which creates more lift. Pre-load is important Keep the lifters a no more than 1/4 turn down from zero lash. some will chime in and say 1/2 to 3/4. That is good for 70's lifters and oil. Comp Cams recomends 1/8. All new flat tappit Hyd. lifters have low quality valving.
Find a set of used 273-318 adjustable rockers buy hydraulic push rods and you will be good. Cheap roller rockers will destroy a motor when the rollers fail and the needles or roller fall into the motor. Those old school adjustable rockers are cheap and will last your lifetime
