Just adjusted valves, car won’t rev past 5k rp, What did I do wrong? Options

[newto914s]

This is the 4th time I’ve adjusted them and every time I do it I feel that I do a better job, but my car keeps sounding worse.
I adjusted them in April and the car sounded and performed great. Around 6 weeks ago I checked the compression and got some low reading (especially on #2, 60psi). So I thought I’d reset the valves and check the compression again. So I reset the valve clearance again and from that point my car has been driving funny. It was very clickity-clack, and wouldn’t rev past 5k.
Now today I reset them again(3rd X in two months), less clicking, but still won’t rev past 5k, unless I only press the throttle down ¼ the whole time.
Is this simple because I set them wrong, or could this be related to my low compression numbers, i.e. valve guides that are so far worn the extra .2mm is allowing valve float?
76 2.0 d-jet

Thanks guys
Samson