F-600

I have an f-600 that is used for a grain truck. It hauls loads around great, but not like it used too, it seems to be lacking power. It also has a major problem with backfiring. I even had a fire occur because of this. If anyone has had similar problems or suggestions plz reply

If it's Holley equipped I'd guess the "power valve" is now leaking, and that wure will cause a fire.