The easiest way to check the condenser is to replace it. Have you checked your dwell. Points being too close can cause what you are describing.
How serendipitous! I just did a tune up on the Blue Funk and am experiencing the same situation! The engine fires up and idles perfectly, but cuts out at high RPMs in 3rd and 4th gear.
I've also noticed that the RPMs don't increase, as they did before, when sitting idling and I rotate the dizzy to the left.
I'm gonna check out what you all suggested!
Thanks!
