rochester monojet leaking fuel

[Jordanbsparks]

i do believe this will be my first post btw, so iv got a 72 c20 with the 250 i6. i have just rebuilt the carb with a bigger jet. was 60 is now 105. i pulled the biger jet out of a chevy stepvan with a 292 in it. so i got it all back togeather with the new jet an all, started the truck and 1 it runs rough and has a mild black smoke and will not idle but also the carb is leaking fuel extreemly bad from underneath the carb through the acc pump arm. i know the float level effects this. iv re adjusted float level many a time with the same result. im starting to think that something else is the problem. would i have to change the needle for the jet as well? i have nfi what is causing this. and this is my dayly driver. if any one out there has had and fixed this problem please chime in. thank you!