Here's a good one!
Thirty cylinders, five banks, five carburetors, five distributors, 1255 cubic inches. This is what happens when Detroit goes to war. Chrysler built the A57 as a way to satisfy a World War II tank-engine contract in a hurry, using as many off-the-shelf components as possible. It consisted of five 251-cube passenger-car inline-sixes arranged radially around a central output shaft. The resulting 425-hp pile of hairy freedom powered M3A4 Lee and M4A4 Sherman tanks.
How the heck do you tune something like this? How would you like to be the first GI to open e engine hatch in the field and find this!