These guys^ did exactly what you are describing, and 20+yrs ago, "Speed-O-Motive" offered a kit to make a "350" MoPar 318. The guys in the video had to relieve the bottom of the pistons near the pin bosses to clear the counterweights, but they used replacement pistons for a super-low compression 318 truck application. You could use a stock 360 crank and have the mains turned down, and the counterweights cut in a lathe to clear, or relieve the pin bosses like they did. The trick way to go would be get a Eagle or other aftermarket crank with 318 mains already and the 360 stroke (3.58"), and use SCAT I-beam rods and a piston by AutoTec or another custom piston, with your desired 318 bore based on a 360 compression height. AutoTec/RaceTec will let you change the bore on a shelf piston for little or no extra cost. Someone earlier posted a 4" shelf piston (SRP?) for that stroke, if your bores will allow. I like these unicorn builds, that's what makes this hobby fun, being creative and unique!!