Holley Sniper and the PCV valve

The nipple on the air cleaner goes to the crankcase breather in the valve cover.
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The PCV valve gets hooked to manifold vacuum, usually through a fitting on the base of a carburetor.
The sniper should have a fitting on the rear that the instructions label as "brake booster". If you're not using power brakes (or if you have the booster plumbed to the intake manifold), use that one for your PCV hookup.
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If neither of those options work out for various reasons, there's a pipe plug on the front of the throttle body that's also manifold vacuum- it isn't mentioned in the manual. Just remove the plug and put a hose barb fitting in there and you'll be good to go.