Wait!!!!!!! you have aluminum heads?
Well then
Let me tell you, I have run the pressure to 185psi AND MORE with a tight-Q and STILL BURNED 87E10. I did that for FOUR or more years, in my Daily Driver, taking the engine apart every winter for inspection. After that, I changed the cam, increased the Scr to keep the pressure up and drove another decade or more.
Aluminum heads is absolutely the best thing you can do for altitude compensation. This opens up a whole new page of cam selection.
