Loud backfires??

[blueneonman1]

In my GT, when I am going over 50mph and drop it down into 2nd to let the rpms rev in a downshift, my car will almost always backfire. Sometimes it does one loud BANG! and sounds like a sawed-off shotgun and other times it just gurgles till the rpms drop. I must admit, I love the shotgun sound and how it makes joggers take a double-step when I do it next to them, but I want to know why it does this and if it is bad. Some people tell me it's timing and that my timing is too retarded. Is this correct or is there some other reason? I have 73,000 miles on my car and have never changed the fuel filter. I'm wondering if that is the problem because it never backfired 20,000 miles ago, with my old engine. Then at around 50,000 miles it started. I got a new engine in at 65,000 miles and it backfired on that from day 1. So what is making these backfires?

------------------
Blueneonman - '95 5.0L Mustang GT Convertible | K&N Drop-in | FMS 9mm Wires | Hollow Cats | Flowmaster 2 Chambers | Subframes | 6-pt Rollcage | 14deg Timing | King Cobra Clutch | FMS Adjustable Clutch Cable | Coolest Neon Lighting on a Mustang EVER!

Best time: 14.8 @94mph