hello, no that is not a possible modification, the design of the entire valve train is different to account for the use of hydro lifters.
My last question, as you know that the distance between the cam lobe contact surface to valve stem contact surface in hydraulic lifter is greater by 9-11 millimeter (if I was not mistaken) compared to mechanical lifter is there any after market mechanical lifter with the same diameter (30.959-30.975 millimeter) in your knowledge that could compensate for this difference?
not that i can think of, that isnt something that i can just plug into a database either unfortunately. Why did you want to replace them anyway? they are a better system anyway