Never done this before (no header gasket)

I have seen our stock car (dirt track) builders do this and now seeing a few people do it on there daily driver, one being a 460 for truck, but it has not been fired up yet.
So
my question here is has anyone ever done this ?
And how did it work for your application?

This will give me even more clearance, and I feel like I will not be blowing out a gasket and having a leak .

Any ideas and help would be great.
Thank you for your time and help