is it worth changing intakes?

The performer will perform worse then the factory 360 manifold or 340 manifold. Most likely your 360 manifold has egr. Swapping to the 340 manifold will get rid of it. The main benefit of the performer is weight. I have run my race car with a 340 and stock 340 manifold to 12.01.

Consider a Performer RPM or air gap. They out perform both the stock intake and standard performer. They make power down low like the stock manifold and carry it to high rpm like a single plane. I run a standard RPM now that I bought at a swap meet for 100.