The system consist of a MSD 6AL BTM (BTM means Boost Timing Master) ignition module and a crank trigger. The signal goes from the crank trigger to the SpeedPro fuel injection unit, and then to the MSD module. The SpeedPro adjusts the timing depending on the amount of boost, so I don't use the BTM feature of the MSD module. The old EFI unit didn't have the ability to adjust timing so I utilized the boost retard feature of the MSD. The timing is set to 32 degrees and retards the timing 1.5 degrees per pound of boost. 8 pounds of boost would move the timing back to 20 degrees.
The crank trigger is for a big block chevy, so I had to do a little work to get it mounted to a Buick! The inside diameter of the crank trigger is a little larger than the lip that protrudes from the Buick dampner, so I made an aluminum ring that slips over the lip. The crank trigger then slips over the ring, and the stock pulley slips over a matching lip machined in the ring. None of the holes in the crank trigger lined up with the holes in the pulley, so I drilled six new ones and sandwiched the crank trigger between the dampner and the pulley. The wheel is so close to the water pump (it hit!) that I had to leave one of the bolts out! A smaller wheel wouldn't have this problem. Also, an aftermarker dampner would move the wheel further out, possibly missing the pump.