65 Barracuda daily driver

Overall "Salma" has been pretty reliable for a 52 year old car. Last week I had some trouble with starting and also stalling while driving. It was cranking, but not starting. First I changed the oil, filter, air filter and spark plugs, mainly because it had been a while. I also changed the thermostat, because it was overheating just a bit recently. I bought a new balance resistor, because that is usually the first thing that causes ignition issues, right? But for some reason I decided to swap the ECU with the old one that was on the car when I bought and sure enough, it solved all the problems. Anyways, I'm pretty sure this happened, because I took everything off the firewall to paint it and it's possibly just a wiring/ ground issue. I would really like to swap in HEI or pretty much anything that is more reliable. I attempted HEI once before, but I couldn't get the wiring right (or maybe the module was bad?!). I've been thinking about the FBO ignition, but I'm not sure, if I want to shell out 200 bucks for it. Any other ideas? Not necessarily looking for more power, but improved reliability and gas mileage. It's a daily driver!

A3-8ZYN0FSuiFnV8e--JybBFEx2DoF9dxQXgvUZSVtl1dJsyULEbAY4bOrkZR4fIwVF5IoFYoauMnw94M=w1376-h1032-no.jpg