A brand new ECI OX-340S with:
7.2:1 Pistons
Dynafocal 1 mount
14mm plug bosses & automotive plugs all round
Dual P-Mags
Low-pressure, engine-driven fuel pump
2 hours break-in on their test cell
But without a carb (Used a Rotec TBI instead)
cost me $25,604 USD, a few years ago, including crating but excluding shipping when the $$ was at parity, or close enough. Shipping was another $1,000-1500, IIRC, airfreight. Then another $3,000 GST and freight forwarder charges on top of that, for close enough to $30,000 AUD.
Given you're considering both a -320 and -360, don't overlook the -340 too. The weight of an O-320, but if you go standard (or high) compression pistons, throw in EI as well, you'll have the more power than your average O-360. I have 20 hours on mine now in an RV-9 and can't fault it.