but all dodge's and plymouth's in 1970 had the emission's vapour recovery system in Calforina with this type of unit. then in 1971 they all had it.
the four vent tubes came from the right side of the tank to four rubber hoses that went to a closed vent tube that resided in the trunk. then one tube which was at the very top of the inside of the tube allowed the gas vapours to be drawn thur another line all the way up to the engine which had a 3 port closed breather cap on the right side valve cap. so two small ports- one from the tank tube and the other from the carb's vent hole port (years before that a small vent that was opened and closed by the linkage on the carb- this allowed the vapours to be open to the air- now a no no!) and a larger port from the breather. then all the unbrunt vapours are drawn from one side to the other to the PVC valve and burnt.
Theory is- all vapours cannot be allowed to escape into the air- so a closed vapour recovery system was invented to keep the epa ? guy's happy. then in 1972 with the lower compression standards the charcol system was introduced.
all other 1970 cars had a single vent tube that came from the tank, up into the trunk and then back down below the trunk floor.
now it is not used- that's ok- 440 4 bbl- what I would do is if that extra steel line for the vent system is still there- I would put a 3 port vapour filter on the car and use the vent line all the way back to the tank to send the vapours back to the tank like the Hemi's did.
John Mac
