[I think that this is interesting as a project, so don't take this a critic.]

I'd like to see some benchmarks too. But I think that this project is not a complete Arc implementation. Some parts are more trick to program and more tricky to get fast code.

For example, I couldn't find ccc in this project ( http://arclanguage.github.io/ref/foundation-doc.html#ccc ) (it's like call-with-current-continuation). A version without ccc can cut some corners and be faster than a complete version.

Racket has a lot of work and optimizations under the hood, it has a JIT compiler and some analysis to detect the parts of the code that don't use continuations and can be compiled ignoring the continuations problems.

Arc has more mutability than Racket, and in some parts Arc goes against the Racket philosophy, so perhaps a direct C implementation may be faster. I'd like to see some benchmarks.

I expect the point is to get from a C compiler to an Arc prompt with "make install && arc". Much later, if you're worried about speed, you can install a C++ compiler and libraries, compile an ancient version of Racket, and do the other steps of the original install.