Linux restricted ASCII Shellcode

Hi all,

I'm testing a simple stack overflow on an application with different filters. I'm exploiting it from the shell via Perl. Different exploit techniques with normal shellcode works perfectly. The problem arises when I try "through" the filter. 
I need an ASCII Shellcode.The allowed "A-Z,a-z,0-9". I have tested many ASCII shellcodes found on the wild, all of them didn't work. All the tested examples were in C style... Do I need to make some change to a C style shellcode to adapt to Perl style?
Sorry for the inconvenience of such stupid question...