I have a personal hunch that the Magnum Beer Barrel intake manifold runers at the rear (#7 and #8 ) flow more air than the front six runners.

Putting 24.5 injectors in these back two cylinders and 23.2 injectors in the front is something to consider to balance air to fuel ratio, and prevent full throttle pinging in cylinders 7 and 8.

Injectors catch screens on #7 and #8 tend to catch any crud coming down the fuel lines, such as bits of degraded hose liner.