@ a 1.425 comp distance, using a 3.310 stroke, the con rod would need to be about 6.500 long400 small Chevy piston
Unfortunately the rod length and the block deck height vary a bunch from the400 Pontiac, 389+060 Pontiac, 428 Pontiac, 402 Chebby, AMC 360 + 040, 455 Olds are all in that size range.
Haven't heard of them gave them a call about 6 weeks to make $2500 Aud so about $1900 USDSpecial Piston Services
Did you try these guys in Melb? or is that where you got the initial $3000 quote from?