GM ECU extra spark pulses needed

[Sergey Stopov]

I have GM  ECU for 4 cyl. Engine that gives two spark pulses 
per one crank rotation (every 180 deg.)

I plane use this ECU for 8 cyl. Engine.  

Is it possible add extra spark pulses that will appear in 90 deg. 
after  each standard pulses.  

Does it difficult task?

Who can make it and how march does it cost? 

Sergey Stopov.