1977 Ford F100 dies out when given gas?

well its a FordF100 with a 351 V8. It starts just fine runs awesome. but whenver i give it gas like a lil more than 1/4 it makes a popping noise maybe a sputter then wants to die if i held it there.But if i slowly give into it she revs right up. another thing is that it idles high then when i tap the gas it idles lower.then if i tap it again it idles high..... what would this be? like a choke cuz whenever i tap it then give it gas when the idle is high it revs right up everytime.sorry if this sounds complicated Thanks!!!