On my 73 2.0 with carbs.so I have gas tank vent going to head that's ok but what do I do with hoses coming from left and right head? Should I join both and put into port at oil filler housing?

No, that's anything BUT ok ...

The crankcase can have positive pressure depending on the engine RPM, meaning, you will blow oil vapors into your gastank.

The tank vent needs to be routed to the air intake, preferably BEFORE the air filter.


The head vents can be routed to a oil catch can, like the one i used on my 2056:



PS: We still haven't seen any pictures of your setup.

yes i know about pics sorry,but as ive taken vent hoses off except gas tank vent ,there really isnt anything to see.so in your set up your useing a breather box with a seperate catch can?i where did you get your bb and catch can,ive seen the tangerine product,but it vents through filter to atmosphere.

i understand now about gas vent,but my carbs are weber 34 ict,with no provision for inserting a vent.where should i place gas vent in this case.

so you are saying to insert gas vent to air filter on carbs,my filters are tiny and have no provision for inlet hose.

forgive all my questions,but my engine has 2 vents at head below spark plugs and one on drivers side almost next to cylinder 2,thats where gas vent is plugged in.

None of the after market carbs are setup for the tank breather. You'll have to make your own connectors.

Here's my vent system on a 72 1.7L with carbs.
Click to view attachment

As mentioned earlier, the gas vent line should not be connected to the head. Both heads should vent to a catch can and then back to the oil filler or to the air cleaners.

That style of BB is not a sealed unit. There are little stand offs on the top. There is a foam filter inside that helps trap the oil vapors, the puddle of oils forms on the bottom, and runs out of the 2 side ports. The foam trap should squeezed occasionally to rid it of oil. You can also plumb the 2 side ports to the head vents as they are open to the valve train area and let gravity do the work.

thanks for all the info.in that diagram the gas tank vent is going to port in fan shroud ,thats where my vent is plugged to. i will get a bb and connect head vents and oil filler van to it.

If you follow the arrows. The hose on the fan shroud pushes air thru the canister, picking up the fuel fumes, then into the carbs.

That's close but still wrong.
The blow through for the C. canister should be a separate hose to the air filter. Fuel venting and crankcase venting should never meet.

just got a empi bb,and a fitting for top of air cleaner to vent gas tank.thanks for all the clarification

Thanks - I'll work on that next time I'm in there. If I move all crankcase vent to 1 carb and fuel vent to the other; will that be OK?