84 rx7 12a 14psi blower ms1 v3 024s13. i have 2 msd6al boxes 1 leading and 1 trailing driving a 12a distributor. Ignition pickup to the ms is an electromotive 60-2 tooth wheel. I've got leading igntion timing working off the ms. I'd like to control trailing as well. I do have an msd programmable timing computer that can drive the trailing msd 6al, but i need an igntion trigger input for the timing computer. I tried to wire the trailing computer input in parallel with the msd 6al leading input from the ms but at 3,500 rpm the msd timing computer tach signal would go nuts and cause severe detonation. Can I built an additional vb921 circuit to drive the trailing 6al box or timing computer.