Yeah, I just happen to have personal experience with this. Unlike some, I don't post unless I have personal experience with subject at hand. I ran a complete season + with 1.6 rollers and compared to the numerous seasons that I ran with the the OEM 1.5 type rockers and the rockers that are currently installed on the car. I went from a best of 11.712 flat to a best with the 1.6 rollers to 11.698. I luckily found a rube for the rollers and sold them for about what I had in them (they weren't eBag specials either) and am still running with the MP stamped rockers.
A couple of other locals are are running with rollers on 440's and they also have gained nothing but are still running them because they have them. But you don't want to believe that so:
run what you want - beleive what you want. This exerpt from Hughes sight even if you don't believe writen words. They also wouldn't right it without back up knowledge seeing how they sell the parts. - In the late 50s the O.E.M. stamped rockers started to fail from the high spring pressure with the more aggressive camshafts and higher RPMs and so-called fully rollerized rockers were developed. For the most part, we are talking Chevys here but you've got to start somewhere. The needle roller bearings were used at the trunion because of the Chevy's problem of not having full engine oil pressure at that pressure point, like Mopars do. Needle roller bearings were used because they can operate with very little oil and no pressure, although they provide no friction reduction over a plain bearing surface. Most high RPM (14000 19000RPM) race engines use full oil pressure to these high stressed areas and use no needle bearings;they utilize a plain bearing type surface. Now this can mean anything from an aluminum rocker or steel rocker to something with a special surface treatment (conditioning) to a material like a D.L.C. (diamond like carbon) coating or some similar frictionless coating on the shaft and/or the rocker. The coated or treated rockers are definitely on the high dollar end of the group but they are the most durable and highest power deliverers, because of the reduced friction and harmonics. 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.
Oh yeah, I personally have seen them break and have little needle bearings scattered through the motor.