For those of you with custom tank setups how are you doing your vent? I recently had a tank made for the car using an internal Walbro fuel pump and housing. Vent line on the housing is 5/16". Run the line as high as I can with one of those roll over valves? Thanks.

vented cap, if you have the filler tube height and can find a vented cap to fit.

Both of these are good options.

I've built a lot of hot rods. The tank vent to the top of the fill tube with a vented cap is my normal go to option, as long as the vent tube is attached to the fill tube above the tank level.

After these two options, the next option would be to vent the tank into a carbon canister and have the fumes sucked into the motor like the modern stuff is. Its a bit more complicated, but if you can't find a vented cap for your fuel fill or a good rollover valve set up. it may be another option.