Rochester 2bbl. Carb Question

[Wilhay74]

Hello again, new to site and love it. Have 1974 Cheyenne with 350 2bbl. Bought this truck as a runner with only 32,000 miles but had been sitting for a while after original owner died so I wanted to replace carb. The new carb I bought came with thick base gasket that had a cut out for a hole on bottom of carb at one of the butterflies and I saw on a you tube video that if you use a base gasket that does not have the provision for the hole/vent it will cause oil to blow out everywhere, yet when I took the original carb off it had a thick gasket but with no provision for that hole in original gasket. So which is correct ?

Thanks

 

[1982GMCC1500]

Can you provide any pictures?

 

[DoubleDingo]

Have you tried Mike's Carburetors? They will have what you need

 

[DoubleDingo]

And post up some pics of the offending part(s)

 

[Ricko1966]

The large hole with pictures of anything. I'm going to have to take a guess and guess that the large hole lines up to hole a hole in the bottom of the carburetor to supply vacuum to the PCV port. Which I would want working. If the valve covers have vents, that's kind of OK. But you'd be much better off with working pcv.Even with the pcv valve blocked off but the one vent tube from the passenger side valve cover to the air cleaner would be enough to keep the crankcase from building pressure and blowing oil if driven nicely, I wouldn't want to take a long highway trip.