The Rhodes lifters I'm familiar with are flat tappet not roller, unless they started making rollers now. Anyway, yes, they work. At low rpm they bleed off oil throgh a special channel in the lifter body and effectively lower a wild cam's duration and lift. At higher rpm they pump back up to normal and the cam works as designed. They do make some noise at idle and low rpm because they loose the preload. Crane makes something similar that isn't supposed to be quite as noisey. I think they call them Variable Duration Lifters, or something like that.
They change cam duration about 6 degrees and are oil viscosity sensitive. I would not expect great changes in performance but with a wild cam, they could tame it down enough to make the engine more enjoyable to drive at lower rpm, in some cases.
bottom end If the lifters did as they say they do, wouldn't you lose all of your bottom end power 'till they pumped up at 3000 or so?
Low rpm torque is increased slightly, same as a mild cam will usually give more bottom end than a long duration cam, but at the expense of high rpm power. Large valve timing events don't do much for low rpm port velocity. Kinda like sucking through a straw, or sucking through a sewer pipe.
Some cam makers will void their warranty if you use Rhodes lifters. Just a heads up. These have been around for a LONG time, I have never heard anything bad about them, but I have known very few folks that used them either. Most cam makers offer a variable duration lifter, but most are not as radical as Rhodes. Even an anti-pump lifter works on the same principle. Dave
Rudy Bidlack runs them in his flamed Maverick. He likes them. After studying his tail lights during many runs, they seem to work good.
