Advancing Cam and cylinder pressure

Hey guys, so i finally know how to degree a camshaft my question now is, my buddys slant 225 has a 268 duration clifford camshaft headers 4 barrel all that nice stuff. but he is only cranking out 120PSI at each cylinder evenly so im guess his compression ratio is around 7:8- 8:1. Motor is over cammd not much low end but decent top end but i was telling him what if we advance that same camshaft 4 degrees what would the cylinder pressure rise to? Slants need more torque. My question is if we advanced his camshaft 4 degrees would he be able to build at least some decent pressure or should we just start milling that head

On a slant setting the cam to 100 ICL is typically optimal.
However with that large of a cam you need static compression.
I would pull the head, measure piston recession, cc the head to get the chamber size, put that with the bore and gasket size to see where the compression is currently.
Is the 268 advertized or @.050?

If you are starting with stock slant six compression, you will not get enough of a dynamic compression bump by advancing the cam by itself to make it really run. You will need static in the 9’s to 10’s to get there.