For what its worth, I was running triples an E88( nearly identical to a N42) on a freshly rebuilt flat top F54 with webbers, stage 4 cam from MSA, and headers. I had to back off timing a little, but not that much.
It seemed fine for me. I only had it for a year before I sold it though.
Just to through it out, with the money I spent on the rebuild and webers, I could have had a nice turbo setup.