340 Build help please.

OMG! I so sorry, dead on correct. My bad. Hold on…

The 340 (LMAO- sigh) should use the KB replacement 340 slugs.

These KB’s should do the trick;
KB KB243.030 Keith Black KB Performance Pistons | Summit Racing

Or these Speed Pro skirt coated forged units Speed Pro L-2316F 30 Speed-Pro Forged Pistons | Summit Racing