I am looking for another road draft tube for my 37 to modify for a PCV system and need to know what all years look like a 37,pulled one off a 39 or 40 cab over yesterday in a local junkyard but it had holes in it after fighting it for a hour.
The COE had a normal truck road draft tube,I was expecting one longer but since the brace was not hooked up who knows. I am trying to make it look all original and hide the PCV,my plan is to insert a freeze plug in the bottom where it vents and solder a nipple to the road draft tube near where it goes into the block and then use a screw in PCV near the carb and run a hose down to the road draft tube around the rear of the engine. The tube from the COE had holes in it below where the brace was attached which seemed strange but after taking a 50 to 52 car 235 side cover off that was worse on the inside then out and the hood was shut so it must have been subjected to a bunch of moisture from the ground.
Since I have the splash pans I need a original style road draft tube so it will stick through the pan,since I have a engine on the stand now is the time to get the PCV system made where it will be easier to make.
Don't want to get this thread to far off course. The PCV aspect caught my attention.
When PCV is added to an older engine, how do you determine which PCV valve to use? Is orientation of the valve important? Where should you connect to the intake system?
I ask these questions because of my observations of a PCV system added to an older engine. The valve is mounted horizontally and it never closes. The system is ported directly into the intake manifold. It essentially has become a big vacuum leak directly into the intake manifold. This is especially a problem at idle.