[Tom Walker]

I think a shared exhaust port on a four stroke/cycle engine is only really a problem when you want to use a tuned exhaust system, which only really works on a head with an individual port for each cylinder. And even then it depends on the firing order. But with most V8s which have a shared centre port, the port has to deal with 2 pulses per crank rev, whereas the others obviously only have one per rev, and those two pulses are not evenly spaced in that one rev. There is often only one pulse separating them. This unevenness makes it impossible to effectively tune the header for the centre port.

All of this matters not one jot on your cooking flattie. In fact it is probably the reason they sound so luvly!