After 4 years of running like a champ, my 440 PowerWagon mud bogging truck decided to give me a giant backfire through the carb, enough to explode the air cleaner. Rev's to the moon in neutral but pops out the carb and stalls with any load.

I have changed plugs, wires, coil, distributor, ecu, ballast, ignition wiring loom, cap and rotor. Changed out the 750 Holley to a Thermoquad then an edelbrock 750.

I noticed during all this my autometer 5" in dash tach started acting weird when cranking bouncing everywhere. A friend suggested I unhook it, and it seemed to "fix" the issue although part of me thinks its just waiting to mess with me again and that that a tach wouldn't cause this.