Hi , Ive been down this road before. Your starter kicking back means your ignition timing is too far advanced. You did not say if you used the stock Damper with your motor. If you did not your timing marks could be off. I would , ensure that my cam was installed with the marks facing. one tooth off can cause all kinds of trouble. Ensure that when your piston is at TDC you are at "0" degrees at the crank damper. Make sure that when you are at "0" at tdc on compression stroke your distributor rotor is pointed at your # 1 wire post on the cap.If it isn't the motor will still run but you will be trying to time it on the #6 cylinder which will mess up everything.(180 degrees out) Number one cyl is the driver side front of car. Firing order is 18436572 cylinders are numbered driver side 1-3-5-7- pass 2-4-6-8. Start with your idle mix screws about 1 1/2 turns out.If its a holley you generally adjust the floats ,engine running until gas just begins to come out of the sight screw on the side of the carb.The adjustment is a screw/nutcombination on top of the carb. My guess is that you are 180 out(ignition) or that your cam is out of time.You did not mention if your running solids or hyd cam and what its specs are( did adjust your lifters correctly, none too tight?). You did not say if you are using vacuum or full centrifugal advance. Good luck ,Its probley something minor like this. Don't panic , just systematically check each item and write down what you know to be true so that you don't get lost. The problem with any new engine is that it can be any problem , confusion comes easy. Good luck