I posted this thread in the 55-59 forum, but I thought I would put it here also to see if any of you could help. I'm installing a rebuilt 1958 283 into my 1958 rebuilt. I've added new valve covers with the two holes for adding oil and the PVC valve. On the 58 block directly behind the manifold is a tube assembly, which I believe is the ventilator tube as was in the 235 that I removed from the 58. This tube was cut off when it was rebuilt and I'm wondering do I need it or can it be plugged? Also the four barrel cast iron manifold that I'm using has the front tube for adding oil. Do I need this or can it be plugged. If they can be plugged what do I plug them with? There no threads in these holes, both tubes just slide in. Thanks for any help, I appreciate it. Les
Hi Les, I would use freeze-out plugs and see no reason why you couldn't plug them both. You have crankcase ventilation by way of the PCV valves in each rocker cover so I'd go for it and see what happens. Andy
Crankcase Ventilation You need a way for clean air to get in as well as having the PCV valve to suck out the by pass gasses else you'll soon suck in a gasket somewheres and cause a serious leak . If you're using the rock boxes with grommeted 3/4" holes on both heads m use the air filter cannist from a late 60's to mid 70's passenger car as it'll have provision to run the non PCV hose to the air filter from the rocker box . there's even a nifty filter that fits inside the air filter and has a hose barb .
Oops ! Sorry , Ii missed where you said one rockerbox had an oil filler , you can simply use the vented typ of oil filler cap instead of plumbing the fresh air intake to the air filter . You might have to look in the " Buyer's Guide " cap catalog to find the vented oil filler cap as they're not common anymore...
