tom
i doubt the stock valve springs would bounce with anything but the wildest cams ( the piper cam leaves only about 2.5mm before the stock spring is coilbound, which does,nt leave much room for stronger ones)
if the oil pressure is ok, i would be tempted to leave the shells in because they are sized and graded to very tight tollerences, but a glazebusting and new rings is well worth it imo
