Yes, factory compression ratio can be a bit variable on a 40 year old production engine.

Lots of good advice so far. As suggested, total performance involves the entire car and sometimes you get greater performance improvements for money spent, from drivetrain and chassis components instead of focusing entirely on the engine, in getting the most performance for the money and effort expended.

Also, when you significantly improve engine performance, other parts of the car start to bend and break. Chassis twist, differential ring gears, u-joints, etc, break.

I went with Edelbrock Heads on my 440, but that was over ten years ago now. I have been happy with my choice, but as suggested, increased compression is like (relatively) free horsepower.