an oil change wouldn't hurt if its been awhile but it sounds like one of the rockers isn't get enough oil at consistant road speeds and RPM's. I would think perhaps a piece of trash may be stuck in an oiler hole? I would pull the valve cover and see what each one is doing. I had one that did somewhat like you mentioned and it just needed adjusting a tat. If hydraulic I've seen a single lifter lose its "prime" and clack like crazy.(spring was broke) Let us know what you find.


1937 Chevy Pickup
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1950 Chevy Coupe
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I'd rather walk and carry a Chevy hub cap than ride in a Ferd.
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