i’m trying to find if anyone out there can help me i am so frustrated 😡 my 57 F600 with a freshly rebuilt 272 with brand new hei distributor/coil new plugs wires freshly rebuilt original 2300 holley carb it idles great fires right up then after about 2-3 minutes a small pop is heard from the exhaust like a faint “dud dud dud” one right after the other with about a 3 second pause. and my vacuum gauge drops one mark (21”) when it’s popping then goes back to normal (22). i retard the timing it pops louder if i give it a little throttle it goes away. around 1,100 rpm it has done this for a while now. but now this time when it’s totally warmed up it will just randomly die and nothing brings it back while it’s dying out. but it immediately fires back up when im driving it it’s fine but when it’s at temp and idles for a little bit it will die. i reran every ground on it with new wire and soldered connections thinking maybe that was the culprit. does it sound electrical? if it does what would i test?? Thanks, john