It's been 30 years since I built a hemi, but I would advise you the same way as canadianal. The springs aren't critical but the rockers will have taken a "set" in their respective positions on the shafts and I wouldn't mix them up. The last hemi I built, I talked to Racer Brown on the phone (yes, I'm that old) and he advised tossing the springs and making steel tubes to fit the shafts and replace the springs, leaving about 0.005" play sliding back and forth on the shaft. This was to positively locate the rockers and prevent the rocker pad from falling off the valve stem which they can do with the springs.