Jess, Backfire is usually a timing or mixture issue, where is your car at? as in recently rebuilt anything, been running fine for a long time before this happened? As far as running hot, try about 1/3 anti-freeze to 2/3 watter and a little Redline watter wetter, this may bring the temp down 5-10 degrees, may be running lean as well. Good luck. Greg Lemon