More hp does not have to come at the expense of higher compression of more fuel. You just have to use what you have most effectly. Alot of tines there is more fuel due to bad adjustments, thst us not being burnt or wasted. Doing things to make the motor more efficient makes my hp without adding more compression or heat. In fact burning all the fuel the correct way will actually decrease temps. Things like correct cans having enough lift and duration matched to head flow. Heads thst flow better or actually have more velocity will mix the air fuel better making more hp. You can add 20 to 50 hp to most 260hp 5.7s and not have to touch pistons. Alot of time 205hp can be gained in just carb and intake. Another 20 to 30 easy with heads and valve work done correctly. Nothing about cam and pistons changed. And carbs can be set up to be quite effenent. But they take work and adjustments where fi just does all that for you