yes i would say you can put a flat lifter cam in one but why would you want to do that ? there is nothing wrong with making the valve train adjustable but you need to use the right parts the push rods many show some small wear you need to look at the push rods check for them for out of round( bent) and you need the right size pushrod length. roller cam push rods can not be used with you flat lifter cam you need to check the valve train for thing hiting that could be piston to valve .valve retainer to guide rocker to stud there can be other stuff but thats a start