What kinds of things cause gas to exit through the header?

this is on my '75 F100 with the 460 in and I flooded it pretty badly a while back all it looks like all the plugs are fouled up. I'm about to head to the parts store and I'm wondering about some other suggestions other than just picking up some new plugs.

 

Even though you dont want to hear it....I think fouled plugs = no spark = no ignition of gas

 

actually I'm HOPING just replacing the plugs will cure it thats an incredibly easy task with how much space this engine has in the compartment of this truck.... now in a tight space plugs can be a PITA to replace but certainly not this one!

 

you'd have to foul alot of them out. i had my #3 cyl fouled out on my topaz (2.3L) and it still started a ran, just dragged *** more than a dog!

 

I can get it to stay running as long as I hold the gas down but I removed the header on one side after I saw some gas coming out so I'm going to replace the gasket on that side.

When I'm holding the gas down to try to keep it running tons and tons of white smoke fills the entire area until I finally give up. I'm going to just replace all 8 on this thing probably tomorrow since its sitting out at my moms house right now.