You need at LEAST 10° of ignition advance. I use 20° and it works great.
This will give you more power and will probably improve your mileage,
also reduce the risk of overheating your exhaust manifold.

If you have not set the dwell you should do so before you adjust timing.

You need to be using a thermostat because part of your cooling system
is short-circuited without one. I'd use a 180° at least until it gets
warm all the time.

If you still have the performance problems after advancing the ignition,
your mixture may be a little lean. I'd lower both jets about 1/3
turn at a time until it runs well without the choke pulled when warmed
up.

Your driveshaft center bearing or one of your U-joints may be going bad.

Hope this is helpful.
--
George Downs Bartlesville, Oklahoma