The early (mid-1970's) Volvos had a Bosch injection system that used an odd/even approach, triggering 3 injectors at a time every 1/2 turn of the distributor. There were two sets of points below the breaker plate, with a timed variable-ground system controlled by the ECM to control injection volume. It was an incredibly primitive system, prone to all sorts of maintenance nightmares, but pretty effective. On a stovebolt, a pretty simple camshaft position sensor could be used to synchronize a true sequential injector controller, or two sensors on the timing gear could be used to trigger a 3-injector setup. A plain old gutted-out carburetor could be used as a throttle body if a stock-appearing system is desired. Just plug up a few idle passageways, etc.
Jerry
