340 issue after camshaft change

I have a problem I’ve never encountered before when working on or building an engine. I installed a new camshaft (comp cams high energy) in my 340 along with a new intake and carburetor. Adjusted the valves per the published procedure then went to start the engine. Engine spun over like it had no compression. I rotated the engine to #1 cylinder TDC and stuck a borescope in to find that both the intake and exhaust valves were open. Found the same on the rest of the cylinders when rotated to their respective TDC position. So back on to adjusting them again to published procedures written by someone else. Same thing with no compression as valves all hanging open. I pulled the front of the engine back apart to check timing gear marks and all appear to be as required.
I’m beginning to question the camshaft and if it was ground right. Anyone else ever experience this? I put the cover back over it and walked away in disgust!