The same script is a shell that is designed for scripting (i.e., a POSIX shell, such as bash, ash, dash or ksh) takes much less time than csh and quite likely less than perl.
The exclamation mark might be a problem. Escape it like you did the space.
Also, empty out or trim or optimize or remove /etc/csh.cshrc, /etc/csh.login, $HOME/.cshrc, $HOME/.login, $HOME/.tcshrc, $HOME/.history
Finally, it's possible csh is so under-used that it's never in the OS's file cache or that there's a disk error on the track locating the executable code.
csh is already my default shell. If I'm running csh scripts, are all of those files (/etc/csh.cshrc, /etc/csh.login, $HOME/.cshrc, $HOME/.login, $HOME/.tcshrc, $HOME/.history) still processed? If so, that explains it. The .cshrc file is huge.
How can I make csh skip those files? You see, csh is the default shell at my company, and the .cshrc is necessary because it sets up a lot of environment variables for our software. I can't remove the .cshrc... so can I skip it?