1991 Chevrolet Silverado Need help with screw size...

I recently bought a crate motor from Summit Racing. It is the 350 with vortec heads. It came with an opening for a crankshaft sensor on the timing chain cover. I was told I didn't need a crank sensor for my year truck that I am restoring. I bought a crank sensor anyway to plug the hold that is in the cover. Problem is, the sensor didn't come with a screw. Can you tell me what size screw, threads, length, etc. would fit there.

thanks for your help!!!!