I agree with the choke problem. If it vibrates closed you wont hit the rpm your looking for.
The other thing Ive seen more often than I want to are ignitions on 361's that fail lowering the rpm. From the list of things that you have done, that is what I would look at next if your sure the choke is ok. Swap on a coil from a known good unit to check.
The other thing Ive seen more often than I want to are ignitions on 361's that fail lowering the rpm. From the list of things that you have done, that is what I would look at next if your sure the choke is ok. Swap on a coil from a known good unit to check.