Pump gas or race fuel?

It kindof depends on what parameters that calculator is assuming and/or what numbers you actually input-ed. You know what they say; garbage in=garbage out.
I calculated the Ica from the 288 advertised, installed at 108.
I used 4.02 x4.00 for engine size, and 6.123 for the rod length, and
used 1000 ft elevation. But I noticed that the elevation-input is not working correctly today, giving the same Dcrs for any elevation from zero to 3000.
That is a nice cam-size for a street combo, so I hope you get it sorted. Some guys here on FABO have reported running 200psi, still on pumpgas, with alloy heads. I myself have run my Eddie-headed 367 at up to 185psi, still on 87E10.
Yellowrose is, IIRC, at 170 on iron heads, an excellent number to be sure.
The 20psi or so difference, between the two heads , is not actually a serious benefit to horsepower production, on the street. The alloy heads NEED some extra pressure, just to keep up to the iron, because of their propensity to steal heat out of the chambers. Heat is power. But, the alloy heads are better at NOT producing detonation as easily as are iron. And of course, are easier to port and such. Plus, a good chamber size and shape, makes power on less ignition timing.

Post up your volumetric specs, and we can help you with the math;