I would like to replace the springs on a project jeep I bought.  Question: I want the same lift the current springs have but I don't know what that is, it has been converted to spring over axles with 3" shackles so is there a measurement I can take to figure out what the current springs are?
The frame is a 78 CJ7
it's my first attempt at anything mechanical so be gentle..Thanks  

I would loose the 3 inch shackles as they are going to compound drive line angles with short drive shafts. I would suggest stock spring since it is a spring over conversion which will add about 5 or so inches to height over stock without extended shackles. My biggest concern here is drive shaft angles for a "beginner" so you do not want to extend lift even more.  

I agree on the shackles, never use more than 1" shackles mostly for saftey.
for your new springs the best ones to use on the soa are factory YJ springs... the ones with square headlights... the cj 7's are just long enough to get away with the 5.5" of lift with the stock driveline, ya can adjust the pinion angle and lower the t-case cross member to obtain the proper drive shaft angle and alieviate vibration. the best route there is a cv shaft. the cj'd handle pretty bad on the hwy, IMO lifted any more than that. then again I've been spoiled by the TJ's,