i have the mnr aloy fuel tank in my car at the moment which has the 2 outlets on the top, plus the filler and 1 outlet on the bottom at the lowest point.
but as i had the fuel pump and level sender from my s2000 donor i have drilled this into top of the tank am am going to use it for the car! this also has a pickup and a return which i will need to use so what can i do with the existing outlets? can i put a small link between the top 2 and a longer peice of hose on the bottom outlet tied to the chassis (higher than the tank) as a vent?

Same issue as used siera sender. Just linked with a bit of fuel hose. Had a seperate vent though to filler cap.

You could block one off with a bolt (that has a sholder) down a short peace of rubber pipe. The other (the return, wich should be to the top of the tank) could then become you vent.

[Edited on 1/11/10 by Bluemoon]

I think you'd be much better off using a top one as a vent and blocking off the bottom one. It's not going to vent properly like that.