Highest flowing sbm heads?

IF this isn't reliable then I don't know what is.

Found this post from 2018:

3000lb demon. 360/418--587 cast iron heads, home ported--.590 Racer brown solid flat tappet-- STX-22--13 to1 CR--timing set at 28*--crank trigger--9.68 at 136mph--1.260 best 60 ft, probably better but tripped the 60ft. timers with rear tires often. 2600+ passes and counting. Went as many as 4 years without pulling a valve cover off. Pistons and crank never out of block since day 1. Dropped a valve in late 2017 but short block survived with only a minor gouge out of cylinder wall. Put a lesser set of heads on it to finish the season, raced it the next night, and still ran some low 6.20s 1/8th mile.