"VR1" I assume is Valvoline 1 Racing Oil? They took all the good stuff out of that oil years ago and it is not suitable for flat tap cam engines without additives. With additives, do you really know what you have? It's better to go with an oil that is fully prepped for flat tap engine break-in right out of the bottle IMO.
Hard to say without hearing it, but I'd pull the intake and pushrods, inspect lifters for rotation and wear, cam lobes, and if good..... swap in an off-the shelf break-in oil, reassemble, re-lube, set preload and try again. It's a lot of work, but at this stage caution is the word of the day.