1968 Ford Mustang — car died once at a light and restarted immediately — trying to narrow this down

Write down what you already tried. A second data point from another 1968 Ford Mustang owner helps more than a generic diagnosis. I'd do that before spending real money. Just my two cents from doing this recently. Might be overthinking it, but I'd rather overthink than overspend.

Don't overfit one forum story to your car. If it still isn't clear on the 1968 Ford Mustang, a specialist hour can be cheaper than another round of parts. That's where I'd start. If they can't show the line item, I assume it's hiding. A day of patience here is cheaper than a wrong part. I'm keeping receipts and dates in one folder.