Edelbrock carb loading up after trucks turned off?

I have a 78 chevy truck, 305 all stock except edelbrock 600 and perfomer intake. The motor does burn a good bit of oil after sitting overnight, and after been running maybe just a little haze. But what its doing is, after you drive it and let it sit say 10 to 15 mins, you go to start it back up and I have to hold it to the floor and crank on it for about 20 seconds sometimes more, then blows black and white smoke. I had a q-jet on it before and it did the same thing, so could it be oil leaking down and flooding the cylinder? any ideas?