So you think drilling out the end cap where the pea shooter would be may be enough? Offcourse the connection pipe will have to be closed off.
Also, the right hand side which you converted into a storage can seems to have a baffle and all sorts of stuff welded in. Did you have any problems taking out all the innards?
I've only got basic tools like Dremel, drill and angle grinder mind you.
FWIW, you can keep the cat while running leaded fuel. It'll just be destroyed, but who needs it anyway. Weight reduction would be the only gain.
Did you have any trouble pulling it out?