how can i remove this part of a block? https://imgur.com/a/Ka68Ffc I cant select it to remove it, an it clips when driving through it.

Probably you've edited this as a custom block. You can't edit the clips of a custom block.

Try converting the block to an item, then these clips will be converted to regular geometry that you can edit.

You can convert a block to an item by selecting the item menu first.