Fuel question

[Robb]

I was wondering if there is any issue with installing a fuel valve in my rv7 that draws off both tanks at the same time ? Seems to me that would be a good idea to keep the balance the same and my Husky is that way and I am used to it

[Mel]

Drawing fuel from both tanks simultaneously doesn't work on a low wing aircraft.
Both tanks will never flow evenly and when one tank is low enough to uncover the pick-up, you will start drawing air and the pump will not draw fuel from the other tank.

[Robb]

Thanks I figured there must be a good reason !!!!!