starting facing downhill

hi murray,
thanks for replying. the cuda will start fine in my garage(level), i pull it out in to my driveway(sloped) and shut it off. if i try to start it again it will crank,but not start. i believe it is flooded, but i checked my float level on my carb and it is fine. if it sits and i jack the front end to level the car out it starts. so far i have checked the floats on the carb, replaced the fuel filter, and replaced the spark plugs. i was wondering what else i should try, any suggestions would be appreciated.
thanks,
tom