The Stovebolt Site Forums The Shop Area Engine Shop oil breather tube

I have a 55 270CI installed in my 50 GMC. I'd like to use the 50 GMC Valve cover but it has no way of letting me add oil or oil breather.

Question is, will the side option work using a straight chevy oil fill tube with a breather cap instead of using the old drafting tube unit from my 228CI? All comments are welcome on this.......
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Grant, Is there any option to get the original setup from the '55 270? Gmc's either had the road draft/oil fill combo combined with a vented rocker cover or a crankcase air intake/oil combo with a "sealed" rocker cover that had a bulkhead 90 which went to the pcv valve and intake valve. In my opinion the pcv setup is preferable. But either will work if you have a vented rocker cover for the road draft. I don't like the road draft on the gmc's because the air drawn in to replace what is "drafted" out of the crankcase is not filtered through the rocker cover. Dust can migrate in there and give moving parts and the filter more work and wear. The pcv setup has an oil bath filtered air intake so that incoming air is properly filtered. Additionally there is always positive ventilation even at idle if the pcv valve is properly working. Don't throw any of these parts away or modify them, both setups are getting a little rare. Too many old trucks are being cubed up for shipment to China these days.

I have both. I kept the 50 crank case tube tube with oil filler access and veneted valve cover as well as the 55 crankcase tube and vented valve cover with oil filler access cap.

What I want to do is use the 50 (old script) GMC valve cover but there is no way to fill. That's why I wondered about the standard small block V8 tube being used as a substitute for the road tube. Seems I would get filtering plus venting at the rockers as well as the cranckcase.

The road draft system uses the road draft tube to vent the crankcase. Air to replace what is "drafted" out the tube comes in through those slots on the rocker cover. A primitive setup. But that is how the road draft is supposed to work.
There are many different versions of the road draft tube. But remember that they are all intended to exhaust the crankcase fumes, except for the pcv equiped gmc's and some 235/261 Chevy's.

If I understand correctly, the draft tube is necessary to get the venting so the strait up standard V8 5 or 6 inch tube with a filter cap would not work?

Thanks for the replies. Think I have it figured out now.