Road draft tube hole

[b1gkountry]

I have a hole on the drivers front side of my 170s block. It appears to have been for a road draft tube. It has 2 bolt holes, and one large hole, but there is no evidence (on carb/spacer) that there ever was one installed there. Nor is there a PCV valve anywhere. Can I just cover, there is a hose on the exact opposite side that does go to the carb. Engine runs good, but haven't taken for a drive yet. https://www.dropbox.com/sh/keoap5cr4xh6 ... afAVa?dl=0

[comethead]

It's a crank case vent so covering it might not be a good idea. Can you rig up a plate and tube for it?
I've seen original road draft tubes on eBay for cheap.

Joe

[Groover]

I have a hole on the drivers front side of my 170s block. It appears to have been for a road draft tube. It has 2 bolt holes, and one large hole, but there is no evidence (on carb/spacer) that there ever was one installed there. Nor is there a PCV valve anywhere. Can I just cover, there is a hose on the exact opposite side that does go to the carb. Engine runs good, but haven't taken for a drive yet. https://www.dropbox.com/sh/keoap5cr4xh6 ... afAVa?dl=0

Pretty sure road draft tube hole = NO pcv valve. Fresh air sucked in the oil fil cap and out the road draft tube. If you had a PCV valve (or evidence of one) then I think the road draft tube hole would have been covered or not drilled out in the first place... I think.

By the way, road draft tube hole is air leaving the crank case (sucked out into the atmosphere), not air into the crank case. Your runs well because the air can escape, but the tube would actually suck the air out which would pull fresh air in via the vented oil fill cap.

[Adams]

Where exactly is the hose you are referring to that goes to your carb? Do you have a PCV valve somewhere (in the valve cover, or in the hose near the carb base)? I'm not understanding where that hose is coming out from. On my engine, I actually added a later valve cover and PCV valve, so the road draft hole is not necessary (although I left the tube on for extra breathing).

[b1gkountry]

After taking a second look, the hose I thought went to the carb is actually just the heater hose that runs near the carb. I am building a plate to put a PCV valve over the place where the draft tube should be. And am thinking about just drilling a hole in the air cleaner attaching a nipple and running a hose to the pcv valve. I can't find a plate adapter for my carb.

[Groover]

Might be easier to cover the Road Draft Hole with a plate and put your PCV in the valve cover with a tube to the air cleaner. If you wanted to look around you'd probably find a valve cover and air cleaner combo with those holes already on some blown engine from the later 60's?

[Adams]

I tried running a tube from the draft tube hole to the air cleaner, but it didn't seem to work well. Unless you send it to INSIDE the filter (which I didnt want to do) you could end up just getting fumes coming out the air cleaner. I picked up a newer-style valve cover with pcv hole and grommet. Your intake manifold should have a threaded plug right below the carb. I took that out and put in a brass fitting for the hose. In fact, I doubt a pcv valve would even work unless you have t hooked up to manifold vacuum.