200 psi is way too high for pump fuel, and no way 'carbon build up' will push it up that high. Try another compression gauge first. And an actual 9:1 compression ratio and moderate to big cam won't end up close to 200 psi cranking pressure... maybe 145 psi. So I really suspect your gauge is off, and if so, it may be masking some cylinder pressure variations. You said 'most' of the cylinders ware at 200?
The only other way to get such high cranking pressures is the timing is waaaaay advanced. That would have to have happened during assembly. If the engine has been running OK, then that is not logical (and things won't fail more advanced).
The exhaust note when you went around back is sputtering and fluttering, like the exhaust valves are not closing properly all the time, or some cylinders are misfiring. So if the cylinders' compression are OK (which is still unknown based on those not-logical compression readings IMHO), that points to valve leaks or intake leaks or cam/valve problems. The sound at the end has a distinct miss going up with RPM's so 1-2 cylinders are not firing right at all.
So was this running OK before?
