350 Crate Engine: Loud humming sound after engine warms up
I was wondering if anyone could help me troubleshoot a loud humming sound on a new 350 crate engine (85' gmc pickup)? Everything sounds and works great when I start the engine...but after a few minutes (engine warms up) I get this fairly loud humming sound.
I have all emission hose connected.
When I lift the PCV valve out of the valve cover the sound goes away.
I check for leaks around the base of the carb and looked for cracks in any hoses, but didn't not see anything...
Pretty much everything on the engine is new: carb, intake, headers, valve covers, distributor, etc.
Any ideas or tips would be greatly appreciated!
Last edited by sofa1515; 01-11-2010 at 02:15 PM.