How to plug front exit exhaust

[Kelby graham]

The guy that set me ski up before me has the exhaust running out of the rear and the front. I am going to take the front exit exhaust stuff out so I can Uber my TDR waterbox. I am going to the outlet in until I do my glass work this winter. What should I plug it with? Any tips or suggestions are much appreciated.

 

[Quinc]

freeze plug.

 

[Big Kahuna]

Rubber cap clamped on the inside. Can get at Lowes.