My 96 z28 its ng an issue where the stereo turns on and off and there is a very fast clicking from under the passenger side dash. Security light flashes occasionally. also if my seat belt is not hooked it bongs the same speed as the clicking

I'm working on an 88 350 when I tried to start it it made a loud clicking noise and id adjust the distributor cap and after awhile it would turn over but now that I try to start it it just mashes a real loud clicking noise it's not the battery or headers please ineed help:confused: