Steve
You may want to run a compression check. It sounds like you may have a couple of burnt valves. This may cause a lot of your symptoms, tick noise when wire off, popping back thru carb, loss of power under load. You can rent (for free) a compression gauge from most chain auto parts stores, Autozone, Advance, Pep Boys, usually you just leave a deposit (cost of a new one) and they refund back when you return it. If you have low compression it would give you all winter to get the heads rebuilt.
Rob
The Eagle's Nest