[twobjshelbys]

InI had the Roush 427IR engine which had the faux 8-stack. They paired it with an Accel fuel injection controller which they had only partially completed the tuning process (it didn't work at altitude). It was a MAF system (the MAF sat in one of the trumpets). After my tuner figured out that the altitude table had not been populated and he fixed it, it ran great. Also, O2 sensor placement is critical. My system had one bung in one header tube but they placed it in the passenger side pipe just after the 4-tube downstep. This placement was subject to getting air backflow at low idle so I ended up raising idle to about 1000RPM and it ran better but that engine also has a lopey cam which contributed.

One downside was that the interlocking of the mechanical linkages can slip and cause one or more banks to be out of adjustment. Get yourself one of the vacuum adjustment tools.

The FI system can be very picky on these. They don't behave like a normal induction since each cylinder is essentially its own throttle body. As each blade opens the fuel flow and air flow changes. The net is that the fuel flow at low RPM (less throttle position sensor) results in a fuel charge with little air turbulance to mix air/fuel and results in rich operation until the throttle blades open to about 1/3. A self learning FI controller can probably handle this but if you have a manual one you should be aware of this difference by leaning it out a little at lower rpm low tps conditions

So the robustness depends on which fuel injection controller you use.

The eye appeal of the 8 stack is unquestionable.