It sounds like you are going lean at higher RPMs, which is a very bad thing. That's a sure way to kill a blower motor. Check your plugs for signs of detonation... little specks of metal stuck on the electrode and/or the ceramic, or chunks missing. Compare your plug colors to this chart...
spark plug color chart
There should be no open ports at the base of the carb. An open port is a giant vacuum leak, which will cause a lean mixture. The ports either need to be connected properly to the PCV, distributor (if you have vacuum advance) and your transmission if it has a vacuum modulator. If the port is not needed for the above, it should be capped.
I would not drive your car until you sort out the mixture issue. It may be as simple as capping that port.
Oh, and welcome to the forums. Lots of knowledgeable people here!