I always build wih the best parts available , so in your case I would use forged pistons so the short block is perfet , things like headers , heads , cams , intakes & carbs can be swapped in later easily pistons not so much .
While I agree the thing is no one makes an off the shelf piston for a 400 that makes decent compression... Everyone who builds a 400 is generally building a stroker... The tallest off the shelf piston has a C/H of 1.908 & those are all KB's...
JE SRP Ross Sealed Power Speed Pro,,, All don't offer pistons for a stock stroke 400... Now if you want stroker pistons all have options.....
My suggestion... Set the 400 block aside for a future build.... Find a 440 block, there are more piston options.....
Until your ready to put allot of money in your 400 your just throwing money away & boring a block that should be put to use as a stroker..
Build a 440 & when you build the 400 stroker later you'll still have the 440 that can be put to use in another car.... JMHO..