the 318 is do able since off the shelf pistons are avalable...

KB makes a dish and flat top pistons ....scat I beam rods need no grinding ...

a cast crank could be used and internally balanced due to the light weight of the pistons and rods...

the 318 .030 would give 390 cu inches...
and since you have 5 blocks...

Tony

70 AARCuda Vitamin C
71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield)
71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas)
71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)