Generally speaking. "piston-fitted" blocks do not include a cam or lifters, so if the oil gallery for hydraulics is present the engine could be built up either way. Given the rash of problems experienced by a lot of people with recent-manufacture hydraulic lifters, the logical approach would be to use either the Sealed Power or Elgin solid lifter cam with the 261 lobe contour and do a valve adjustment occasionally. As long as the rocker arm tips are in good condition or they have been reconditioned to the proper smooth contour, solids are very quiet. The "Singer sewing machine" valve rattle people talk about from a stovebolt engine is just caused by improper valve adjustment or worn valve train parts.
Jerry
