IDGAF what anyone says - I used to run the 2 into 1 Toomey spark arrestor and it was a sweet setup! That motor must have liked the back pressure because I swear it had more grunt with that 2-1 spark arrestor.
All it will take is some slight fab work and Im sure you can get it done.... Or, to make it easier, just run a complete T5 setup. T5 is a great pipe for all around riding, I always loved them and ran em for years.