C4StrokerFun

We have a 383 Stroker crate motor customized that has less than 5000 miles on it. It has 11 to 1 compression, AFR heads, 750 Demon Carbourator, MSD distributor, MSD Coil, MSD 6AL Ignition Box. Approx. 550 HP, peak power at 5800 RPM. Installed in a 1985 Corvette, used for street as well as High Performance Autocross weekends. We upgraded our alternator to a Power Bastards 225 to accommodate high speed electric cooling fans and other accessories. When we purchased the alternator they sold us a 0 gauge cable for positive terminal of battery to alternator, they did not send same gauge ground cable, which we have read may have been necessary. A few weeks ago heading to Daytona we had bad misfiring and smelled burning, when we pulled over the 0 gauge wire was burned on battery end and had melted and blown the 225 inline fuse. We removed the wire and drove home Afterwards none of our electric fans would work. We took car to mechanic who found there had been a small fire and melted wires near the starter where a number of accessory wires were attached. After repairing these wires our fans worked. but we have auxilary pit lights that are still not working and we have to track that down.When testing after this wiring was repaired The car continued to have misfire when cruising at around 2000 RPM but not at idle, and not at high RPM. We ordered all new spark plugs, MSD plug wires and new MSD distributor cap and rotor. Mechanic showed us distributor cap had bad arcing buildup but all other parts looked fine but we replaced them anyway.We got the car back and it is greatly improved, but we still notice a small misfire at around 2000 RPM, but not at idle or higher RPM. The misfire doesn't seem to rob horsepower, it is just very annoying. The car is capable of up to 175mph on track. Could this be caused from a bad ground wire, or a short somewhere in the electrical system? This all started after the incident when the 0 gauge cable and fuse blew and we suspect that happened when the possible fire happened near the starter. We have read it could be from vacuum line, or carburetor needing tweaking. We did add about 8 gallons of 100 octane AV fuel right before we headed to Daytona to run, so is it possible by coincidence the fuel is causing the misfire We did not tweak the carburetor to adjust for the fuel. We are going to run that fuel out and go back to 93 octane. Any insight you could give into this mystery would be greatly appreciated

bjankuski

I would suspect the carb tune is off with the av gasoline, wait to change anything else until you are back on your normal fuel.

C4StrokerFun

Thanks, we were thinking the same thing... it's such a coincidence the electrical issue happened the same day on the way to the track....