I recently installed a Holley terminator xmax on my 2000 Silverado and was depinning the old harness. I was working on the harness under the front of the timing cover / power steering pump area where the purple starter wire runs and noticed a bundle of ground wires that run to the block (not the ground cable from the battery to the block) . I kept one of the grounds for the starter relay but am I safe to remove the rest of the ground wires? Thankyou!

 

You can remove all of the grounds then add new, larger, ones. That's what I'd recommend.

 

You can't "remove grounds".

Every one of those is busy carrying current, from somewhere something sometimes, back to the battery. Since the block is the next electrically closest thing to the battery, many things are grounded there.

As said, you can upsize the wire they're made of; may not do a damn thing, butt sure can't hurt; butt you CANNOT "remove" them.

 

Yep, ground connections are very important