You should be able to crank it up around 40-45 in the low load areas. That's where my trucks are and they don't seem to mind. Do you have a knock sensor setup with that?
I have vortec heads so they don't need that much advance plus if you take a look at the graphs for the run I can only draw the timing back a total of 25°. On our 602 and 604 crate race engines which are 5.7 we ran 36° total timing. I don't need a knock sensor