S.O.S. I need some help here....

You have a 360 engine in you car I think and all you need to do is take the cap off the distributor and take # 1 spark plug off place your finger on the hole and turn the engine over slowly till you feel air coming out, That would be your completion stroke. Look at your rotor and make sure it is pointing to #1 plug wire. If it is pointing away from the 31 plug wire just pull the distributor up about an inch and turn the rotor 180 degrees and drop in back down, There is only two way a 360 distributor will go in.
A back fire sounds like it is 180 degrees out.
Do you have a rv or hp cam shaft in it ?