You really messed up the idle mixture screws. They are not the idle speed setting. Hopefully you didn't screw them in really tight and damage them. With the car off, turn them all the way in (gently) until they seat. Then loosen them 1 1/2 turns (make sure you do this exactly by noting the orientation of the slot in each screw). Note: as you loosen, every time the slot is in the same position you have loosened it 1/2 turn. 1 1/2 turns is a good starting point. Both screws need to always be adjusted the exact same amount (ie. 1 1/2 turn). Once you have the overheating sorted out you can adjust them further (I wouldn't run it too long if it is getting as hot as you say). If it's running too fast adjust the idle speed screw, it's one screw (on a tab on the side of the carburetor or on a cam on the outside of the carburetor) , usually near the side of the carburetor where the rods from the gas pedal hook to the carburetor. It kind of stops the return spring from completely closing the throttle plates. To further adjust the idle mixture screws you have to understand what they do, basically they are tapered screws that as you loosen them allow more gas into the air/fuel mixture. Tighten them and they reduce the fuel. For the car to run properly these have to be adjusted exactly to get the best fuel mixture. These are idle mixture screws, as they affect the mixture when the throttle is closed or close to closed. They have a huge impact on smoothness of idle and how the car moves off from a standstill (under normal driving when you gently squeeze the gas pedal). If they are completely closed the engine won't idle, because it isn't getting any fuel. Theoretically, as you open them (say 1/4 turn or 90 degrees at a time, first the left and then the right), from close to closed, the engine will speed up. After a few iterations of opening them more (again 1/4 turn at a time) the engine will no longer speed up. Keep going and after a few iterations the engine will actually slow down (called rich fall off). Then if you started to screw them in the opposite would happen, and after a few times, when the engine slows down as you turn them in you've reached lean fall off. Basically you want to find the lean fall off point and then loosen the screws 1/4 turn from that point (you can play plus or minus 1/8 turn from this point if you really want to get it perfect). So to actually make the adjustments, I'd recommend hooking up a tachometer so you can see the actual engine speed. Start the car at idle, turn out both screws 1/4 turn, to make sure the engine doesn't increase in speed, if it does loosen the screws again another 1/4 turn. Repeat until the 1/4 turn doesn't make much difference. Now you want to turn both screws in 1/4 turn at a time, repeat until the engine starts slowing down noticeably. Once it slows down, loosen the screws back out 1/4 turn to get to the last point where the engine had not slowed down yet (this is the lean fall off point). Now loosen both the screws another 1/4 turn. This should provide you with a very good idle mixture setting. Now adjust the idle speed as per the factory settings using the tach. This should provide for a very good idle mixture. It should take about 5-10 minutes of idling (which is why I'd recommend waiting for this final adjustments until you fix the overheating (start with just them each loosened 1 1/2 turns from seated). Drive the car and check how it accelerates normally with gentle throttle from a standstill. You want to minimize hesitation when you accelerate and for the car to move off smartly. To try and optimize the settings, you can adjust the screws either in and/or out by 1/8 turns and test drive to see if it improved. Remember to always keep them the same number of turns. Good luck. As for the fine adjustments, running with them turned in closer to the lean fall off point will get better gas mileage but poorer acceleration, further out will reduce gas mileage but improve acceleration. All of these fine adjustments happen within about 3/4 of a turn.