71 challenger tank vent

I have a question about the vent lines that go up inside of tube in the trunk
Why are 2 of them 3/8 and the rest 1/4 and 5/16
the tank tubes are all 1/4 and which goes where
I believe the 5/16 goes up to the valve cover but the others go to tank
Thanks

The four tank lines are connected straight to the pipe. The fifth line goes to the three nipple breather on your valve cover. The breather also connects to the carb bowl vent and the air cleaner

Yeah I got that but why is 2 of the tubes that goes into the neck 3/8 ?
and all nipples on the tank are 1/4 is/was there some check valves inline to/from tank??
I'll make it work but was askin the experts just what is what