I have a brand new in the factory set of ISKY needle-free hydraulic roller lifters(the world best HYD rollers). the part part number
#3975-HYRT. here are the factory spec's from ISKY EZ-Hydro lifters max 185lb closed pressure and 535lb opened. and good for up 7500rpm. are designed for hydraulic roller racers operating in extreme loading environments. These needle-free, high performance lifters offer silent-running, trouble-free HP reliable hydraulic rollers with solid raceway bushing rollers. They also offer a special hydraulic roller body for reduced travel, to allow for the use of more aggressive hydraulic roller cam profiles and higher rpm. Reach for the extra insurance of Isky EZ-hydro lifters and eliminate the possibility of bearing overload failures. the 1st $800.00 plus shipping get's them. save $100's over mail order pricing!