Rab H

hi guys, im new to this so be gentle with me.

I was repairing the rear craddle on my early 90 s legacy turbo, when i had the craddle out i decided to repace the metal fuel lines above the tank. A previous owner had replaced them with rubber hoses which ran through the oval tank unit/ pump cover, across the boot, and into the rear of the car where they joined the metal pipes.

As i reassembled i tested the fuel line by removing what i thought was the return pipe at the engine, after which i blew down it. To my surprise, the pipe was running to the pump side of the sender/ pump assembly.

From what i can see, the pump was pumping through the outlet to the rail, and filtering the fuel on return. Is this possible? What would happen when the incomming fuel would reach the pressure release valve from the wrong side?

Maybe ive got this wrong, but as far as i can work out, the furl feed pipe should go through the filter and join onto the front most, highest pipe of the three fuel pipes on the engine. Shes not like the imreza where the in pipe on the rail is the highest of the 3 vertical pipes, the old wagon set up is more on a horizontal plane.

What do yis think?