Yes a HEI will drop in if its from a 6 cyl. 292 or 250. It sounds to me like its a fuel problem. Ignition problems don't normally care if you run the engine faster, they eather work or they don't! HEI will be a big inprovement over the points, I replaced a brand new points dist. with HEI and was really suprized at how much better it ran. Set the timing where it idles best and test drive. My '73 manual wants them at 6 degrees advanced, I run mine around 8 degrees.
Yours sounds like a fuel delivery problem. Crap in the tank plugging the pickup tube, or a fuel line sucking air. When it dies, get out and look down the carburator and see if it has fuel. Also take note of the engine temp. If its running lean, it will be hotter! A vacuum leak will do the same thing, check around the intake mounting bolts with a hose and listen for a leak. Joe
