Im almost at the point of getting a honda!

I switched to a clear glass fuel filter and I've never looked back, I like being able to see what's going into my motor.

Your car sounds EXACTLY like my 273 I had last year. Exact same problems. It drove me crazy. I changed the points. Changed to electronic ignition. Changed the carb. Changed the timing chain. Changed the intake manifold. Eventually I changed the motor! :)

Actually, I finally came to believe I must have a head gasket problem and pulled the heads off. While off I decided to take them in to be checked and the machine shop said they were toast. My cam was worn too and there were just too many strikes against the old 273 so I took it to the dump and threw it over the wall into the scrap metal pile....damn that felt good! I installed a 318 I got for free and except for a bit of a timing thing it's running great and I can't believe I didn't put this sucker in 5 years ago!

I know this doesn't help, but you're not alone.