On my 65 289 I have a breather hose from my air cleaner to my oil cap, can I remove the hose and get a closed cap on my vavle cover. Is it going to change anything good or bad?
Can you do it, yes. Should you do it, no. The proper design is to have a breather on one side going to the air cleaner or a cap with a air filter and a pcv on the other going to a vacuum source on the carb. This allows the crank case to breath properly, which is needs to do.
What you can do instead is pick up an open-element breather cap. Instead of a hose connection, it just has holes underneath and a filter inside. I've got one on mine. You do need some form of breather there, though.
Printable Version
Do I need the breather hose - 
