Can anyone with a early v.1/2 OEM dump valve measure the outside diameter of its ports as accurately as possible, please?

Even better, how about posting a pic up with a ruler placed across the port...

This one:-




Thanks in advance.

 

Here ya go mate, i make it 21mm

 

beat me to it

 

Fantastic guys - thanks a lot... I can now order a suitable step-down silicone so as to retain the Forge OEM pattren DV when I fit my FMIC (the Hyperflow kit's DV port is 38mm!).