Do you need to have a windowed piston if you have a third transfer port?

[Aidan go fast]

I already have a third transfer port ported out for my reed valve set up and I was wondering if need to install a windowed piston with it or not?

 

[GW's Motorized]

Idk, give it a shot if you have the valve. There's no harm in trying

 

[ImpulseRocket]

I already have a third transfer port ported out for my reed valve set up and I was wondering if need to install a windowed piston with it or not?

In theory you don't, but it depends on how big that third transfer port is. A small window on the piston is usually sufficient to make up the difference if you do decide to run one.