Vented Fuel Cap 1970 Fury

[MONC440]

So I changed my fuel tank and used a B-body tank. No problems with using the b-body tank but it didn't have a built in vent. The new sending unit had a supply line and a vent line but I used the vent line for my fuel pressure return line. So now my tank doesn't have a vent. Last night I have drove the car about 20 miles and when I got home I could hear the electric fuel pump whining loader than normal. I should have pulled cap at that time to see if the tank had a vacuum in it but it was late. This morning I started it up and the pump sounded normal. Anyway I'm thinking a vented fuel cap should solve the problem as I don't want to drill a hole in my tank. So my question is has anyone used a vented cap and if so what one. My other option would be to pull the filler neck and weld in a vent tube that leads up above the tank behind the bumper.

 

[CBODY67]

Which B-body application tank did you use. I need to get a tank for my '70 Monaco, which also fits back to our '66 Newport and the same tank as our '72 Newport, only difference is the number of vent tubes between those three applications. Any vent lines will need to be above the rear axle level, not the rear bumper.

There is another thread in here from a few years ago where a guy used a B-body tank, but no mention of any issues with the vent lines. NOT to forget the significant price differential between the B-body tank and a C-body tank, with the B-body tank being about 6 gallons smaller.

Just curious,
CBODY67