Help - 1987 Mondial 3.2 only fires on front bank of cylinders

Only firing on the front bank (5-6-7-8) of the engine. A friend and I went over the car today - suspected it was one of the coil packs so we took them off - cleaned them up and all the connections and switched the packs front to back and vice versa. No chnage in the problem, rear bank still will not fire, however the rear coil pack (the one not firing) get hot as you run the car while the front one stays cool.

I've read on some posts here that there is another circuit board and ECU in the rear trunk area some place, I've pulled back both sides of the rear panels inside and don't see anything that looks like it, where do I find it?

Also is there a good and reasonable source to get a full workshop manual for this car?

Any thoughts on where else to look are appreciated - was hoping to drive to work in the Ferrari for my birthday this Friday - looks like a no go.