the time before last when i took my carbs off i forgot to turn the petcock back to on instead of off... the fuel pump (or vacuum) was still strong enough to get some fuel in there, but the bowls would empty out and it would eventually die... i had to stop and idle or turn it off for a few minutes then start up again.
it sounds like you are having fuel delivery problems. when dealing with carbs, RPM doesnt matter too much so much as throttle position. what throttle position are you at when it bogs at 5k?
heres a good graph
sounds like your pilot air screw is not properly set? i was just reading about this. they say start at 1 or 2 turns out and keep going half turns out until it idles when warmed up, then adjust out while its running at idle until you get the highest vacuum (or highest rpm at idle), then adjust your idle screw to bring it back down to proper idle rpm