Dual tanks, without mechanical fuel pump?

[kipps]

If your electric fuel pumps have foot valves, what you describe will work. If one or the other of them does not have a check valve included, you'll be backfeeding fuel through a pump, and filling the opposite tank unawares.

I'm doing something similar with an LS swap. Since I'm using regulators, the possibility of backfeeding the wrong tank is much more real. I'm eliminating the switching valve, and both in-tank pumps are teed together using a shuttle valve. The shuttle valve is simply double outlet check valve. Picture two check valves, but they happen to share the same check ball. This way, either pump and regulator can supply the fuel rail, neither can backfeed to the opposite tank, and when both pumps are shutoff, fuel in the rail does have a route back to the tank if it gets hot and expands. I'm not sure if this last reason is really a factor, but I figured I'd rather be safe than sorry.