Reproduction domed pistons can be purchased from Egge or Kanter. Egge was out of stock back in December. They may have made some since then. Both are shorter than stock and so make less compression. The Egges are shorter than the Kanters by about .020".
The reduced compression height combined with modern head gaskets, real world chamber volumes and taller than spec deck height puts you down in the low 9's pretty quick.
