Doing a swap using an 09 Silverado motor question about sensor on timing chain cover

[Bulldog88]

I'm doing a swap using the motor out of a 09 Silverado and have a question about the sensors on the front side of the motor, on the timing chain cover, do they stay or remove them? or replace the timing cover with one that doesn't have the sensors? What exactly are they? Will the engine start? thanks in advance