What octane fuel is recommended for a Chevy 350 with MSI ignition?

Answer 1

i would recommend no less than 87 octane but it all depends on compression ratio ie. upto 9.5:1 ratio u can get away with as low as 87 but recommended is 91 or higher. i run 11:1 compression with an msd 6AL and 235 pro lightning race heads on a street driven 550+ hp 400 sbc and i use autolite 24,25 or 26 plugs depending on time of year {colder in the summer & hotter for the winter) and i set gap for all at .047" . i use 91 or higher octane fuel only and timing is set at 38 degrees total timing under load. or around 12-13 static timing at idle no vacuum at dist.