I have a flatop carbine with front sight block. I want to scope it. Is there a scope mount that will clear the front sight post?

3x and up, you wont even see the front sight even if it was right in front of the obj

First, you should have posted this question in the Optics forum. That's what it's there for.

Second, you really don't want nor need a mount that will put the optic's glass over the front sight. Even lower power magnification (3-4X) will turn the front sight into a blur. If it really bothers you, you can always get a front flip site.

For almost all optics, it is best to mount it as close to the bore as possible. This will make it easier to make shoots at distances less than the zero distance without using excessive holdover. For ARs, it's simpler if you mount the optic so the center of the glass lines up with the iron sights' axis (or where the iron sights would be if you use flip-up sights) which is around 1.61" above the bore. This will allow you to zero at 50 yds and keep your POI within 2 inches of POA out to around 225 yds. This is referred to as the Improved Battle Zero, or IBZ.