I think the guys are on to it with the valve thing. If the head came off the valve or if a piston was breaking up, you would have lots of noises. If the valve is not seating, all you will get is a loss of compression, which is what you are describing.

We get alot of Chevy heads (at our Marina) where the valves are recessing into the heads. Our one engine supplier said it is known Chevy was having a problem with their 350 heads. We are also seeing lots of valve heads breaking off and destroying the piston and cylinder walls in the process.

You may get away with just a new head and/or a valve job.


Don