New 383 wont fire

i would start over . get you a piston stop or make one. bring the #1 piston up until it stops. verify the balancer is right BTDC. pull the cap and verify the rotor is firing at the number 1 wire at the #1 terminal on the cap. double check your firing order and rotation on the cap

if the cam was installed wrong chances are good you would be bending pushrods. but it could be off just enough to screw everything up