A PCV system needs to let air into the system as well as to evacuate air, via the PCV valve and into manifold vacuum. The bottom of the draft tube is designed to create a low pressure area to evacuate fumes from the crankcase, so it would be "fighting" the vacuum provided by the PCV system.
Another problem you have with your current setup is "where do you add oil?" Kill two birds with one stone, or two valve covers in this case. Block off the draft tube. Get two valve covers with breather holes. Leave a breather in one and use the other to feed crankcase air through your PCV valve and into the 1404 carb.
An alternative would be to remove the draft tube and plumb in a fitting that would provide a connection to the PCV valve and on to the carb. Then replace one of the valve covers with a breather type valve cover. That is how I plumbed a PCV system into my '57 GMC V8 with an Edelbrock 1404.
Last edited by Bill Hanlon; 07/21/2023 1:15 PM.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12
'52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
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