Is "6 bit packed ASCII" an effective encoding to obscure text data?
No. I actually new how to do such coding on my MSX machine in the mid-eighties (when I was 12). I'm pretty sure I could have decoded it back then. Note that binary code was much more used at that time; you had to code in assembler to get any kind of performance. It was also pretty common to compress things in such a way because you did not have much memory either.

What you're describing is an encoding scheme. Encoding is something different from encryption. Obviously it can obfuscate text, but that obfuscation is just skin deep. This is especially the case if somebody starts to look for strings.

You could however encode to base64 with a different alphabet. That kind of obfuscate things enough that you have to revert the encoding to read it. You could also XOR your scheme with a (multi-)byte pattern to make things less readable for humans.