Max cyln pressure on pump gas ?

Had to chime in on this one after reading, a few things.

Did a wet and dry compression run on an engine a few days ago for a guy with some of the highest readings I have ever seen (on pump gas) at 245 psi (dry) on all cylinders with a variable of only 5+/- psi. Engine had 3,000 miles, ran on 87 octane, but had fully adjustable intake and exhaust cam timing. I say "but" because cam timing/design has a lot of effects of cylinder pressure and dynamic compression.

Aluminum heads can help in raising cylinder pressures, in theory. Aluminum dissipates heat quicker, and we all know heat causes detonation. So if our combustion chambers are not as hot as with iron heads we can bump up the compression/cylinder pressure. This holds true if the heads are exact copies with the only difference being iron vs aluminum, but when we change chamber design, quench point and area, and a ton of other things we can fiddle with the outcome and it can be either positive or negative.