Mail Subject Has Length limit !!!???

Giganews Newsgroups
Subject: Mail Subject Has Length limit !!!???
Posted by:  solar_w (jin83…
Date: Tue, 25 Dec 2007

when my mail subject is very long as 'aaksjflaskjflkjslkfjsldjflskdjflsjdflkjljsldfjsldkfj',
then send it. I will receive this mail in Unrecognizable code.

If  my mail subject is not very long ,then i will receive the mail ok.

I found in the source code unit IdCoderHeader.pas which has a function "EncodeHeader" : The MaxEncLen = 75 .
If I modify this value to 200 , then the mail subject length could be longer.

I Has the Question : Why  MaxEncLen = 75 ? Could it to be more Lager ?