I think the last time I addressed this was on the GSCA BBS. The problem persists. While cruising at highway speeds, sometimes the engine will begin to miss/cut out and backfire through the carb. It will accelerate and smooth a bit if I step on the gas, but persists at constant speeds. It eventually goes away; on its own time. Its a 350 with a Holly 600, electric choke (that may not be working). New: module (converted to HEI), plugs, wires, fuel pump/filter/lines, thermostat. Fluid levels are fine. No exhaust (it fell off, waiting on student loan to put a new one on). I rarely drive the car as I'm a grad student, thus I've not had much opportunity to notice the problem. I had put a new module in the last time I brought this up, and it seemed to improve things. However, the problem was never consistent.