I need help with my tri-power

I have a 1965 chevy panel truck with a 230 L6 it has open headers camero ignition and distributor and it ran hard and strong then I put a tri-power on it and now when I get it to idle without dying it will only idle above 2000 rpm's a couple of times when I started it it shot right to 7000 rpm's and it blew my rear main seal all carbs are tuned to1/2 a turn out on the fuel and the idle screws are all the way out what can I do to get it to idle normal and low 750-1000 rpm's and stay idling

 

we all have tri powers & problems .You might try a intro , before asking questions . you might have better luck getting answers !