When I look at that gaping maw of a plenum with stubby little runners I see a chaotic hurricane of fuel mist getting slapped around by induction and reversion pulses. At low rpm the fuel is likely puddling on the floor. At the hit the end cylinders are getting a big gulp of dry air and the centers aren't doing much better.

That thing needs air flow. Big air flow. Bigger than that. A 440 will need scary rpm to make it work and will struggle getting up to speed. Big inch engines (bigger than my 541) would likely do better with it but, again, you'll have to work to get into the usable rpm.

Just my amateur eye speaking.

I do like some of those runner mods.