The most disappointing thing about this thread is that they never built a production radial car engine.
But they did build a production radial engine tank - many of the M4 Sherman tanks (49,000 built) had a Continental R975 Whirlwind radial engine. Interesting the M4A6 Sherman had a diesel Caterpillar D200A radial engine. "The Wright RD-1820 was converted to a diesel by Caterpillar Inc as the D-200 and produced 450 hp (340 kW at 2,000 rpm in the M4A6 Sherman". Who would have thought the engine family commonly fitted to the DC3 was also converted to a diesel?
But radials were fitted to a few road vehicles......... Looks like a corn cob in this monstrosity:
https://i.pinimg.com/originals/f8/7c...a0f4cd3604.jpg