Unless you are running a lot of cam with a lot of spring pressure you will be as well off with a set of doctile iron rockers. You will also have to make sure that you have enough spring and also clearance between the valve retainer and guide & seal for any added lift. no matter what rocker you use. Here is an article from our own Dulcich:
From Hughes: The needle bearing rockers are a fairly cost-effective solution but they have reduced life expectancy. All the pressure and shock in the valve train is concentrated on 1 or 2 needles at the most.
The rockers only rock in a small arc of approximately 25 or 30. If the rocker or the shaft actually rotated the needles would live longer. Here again is a conundrum. The smaller needles spread the load over more needles, but they are more fragile you just cant win! Some of the roller rockers even have needle rollers in the roller at the tip of the rocker. The unit loading is very high with needle bearings. All these extra parts are just more points of potential failure.
