I have a 1992 Z71. I had a 350 tbi knocking so i replaced it with a rebuilt 305. Now the 305 is knocking after just a couple of hours of use. Before I pulled the 350 I changed the oil pressure sensor and the plumbing to thread it into the block. I also changed the dizzy cap. I took the wires from the fuse box for the injectors and ran a separate fuse because the contacts in the fuse box were not holding securely on the fuse any more. I don't know if the fuse box itself needed the power wires I took off for other fuses or circuits but I only took off the two wires for the injectors. Then I changed the manifold gaskets on the 350. When I got the manifold sealed up I forgot to ground the wiring harness. This is the ground right in front of the thermostat. I ended up smoking the ignition fuse so I replaced it. Then the fuel gauge started acting up going from the fully pegged position back to normal and then staying pegged. then the oil pressure gauge started messing up reading low and unpredictable. Then the knock in the 350 started getting louder. So i pulled it and all of the main bearings except the front and the rear had been spun. I don't know if this was caused by bad wiring, sensors, or detonation or if it was because of lack of oil. The new 305 lived for about 2 hours before it started making the same knocking noise. I was thinking it had to be something in the ignition detonating but I cant figure it out. Now I'm down two motors and broke can anybody help me with this. I need to know if some sensor or wiring issue can cause this kind of damage and what do I need to check for if it is the ignition. Please help I don't want to put another motor in and have it destroyed again. Thankyou.

I can send pictures of the grounds im talking about and the fuse box situation if anybody needs a better idea of what I did