Back firing problems on 351 windsor?

There can be a number of reasons for the backfire. If you changed plugs you could of crossed 2 wires. Same if you have just changed the dist cap. there can be a crossed wire or you didn't put them back in the same place. Bring the #1 plug up to top dead center on the compression stroke then remove the dist cap & see if the pointer is pointing at the # 1 plug. Check to make sure the wires are in the correct firing order at the cap & trace each wire to the plug that it is suppose to go to. Another reason if you removed the dist from the engine it may not of been put back in in the same place. Worse one is you may have a bent or burnt intake valve. Also look for carbon tracks on inside of cap or a small crack on cap. replace it you see any. You can check the condition of wires/cap at night. Must be dark-start engine & look close at wires & cap. Any sparks will tell you that can be one of you problems WAtCH OUT FOR THE FAN & ANY MOVING PARTS I talked to my son on this problem & he told me that the rotation goes in the opp direction then a 351 cleveland. Check the rotation of dist & wire your cap that way