Just as it says.What size freeze plug for the butterfly hole?Thanks

 

20mm according to this:

Gutting the Exhaust Back Pressure Valve

but some have had a hard time fitting a 20 mm and used a 3/4" instead

or you could just tap it and use a 3/8 pipe plug

a carriage bolt, with the head inside the valve and a flat washer and nut on the bottom also works

 

Dosn't Bean have a billet EBPV delete?........ I can't remember

Cowboy Steve