i went to start my 91 f-150 with 300 and it makes a really wirrd winding noise and wont fire it smeels like unbernt gas and smoking comming out of exuast it will fire a bit and backfire bad but wont start im thinking the timming is mesed up but just happend out of noware has been running and choking out since i bought it and i romoved the cats 2 weeks ago and dint help

 

Check the computer for codes, this thread will explain how:
https://www.f150forum.com/f10/how-retrieve-trouble-codes-obdi-10907/