when I was running a 250 in my mustang I used 427 ford pushrods they are ball and cup style,I had to shorten them,used a tubing cutter,they did not make adjustable style pushrods for a 250,I also would use adjustable valve train on hydralic cams before I switched to a solid lifter cam,I was having problems with the lifters pumping up over 5000rpms,I would them shift between 5800 and 6000,I ran it up as high as 6500 but it was falling on its face.just an idea and some info for ya.