I have a preban colt lower and I want to use an M16 carrier. The M16 carrier not having the cut interfers with the block over safety. Can I safely remove the block and how? Thanx!

I won't even get into yet another debate about using M16 parts but I would ask why you want to use the M16 carrier? If you want a heavier carrier, or like the extra meat protecting the firing pin, just get a different updated carrier that's made heavier, they are out there.  Milling out that damn block could take some work - it's been done, but not the easiest metal to mill, and requires equipment.  Easier to mill your carrier.

I am a little tired, it's late, and I may have just spoken a load of B.S.  Someone help me out here.

You can use a Bushmaster 'full circle' carrier instead of an M16 carrier if you want more bulk with no problems from the sear block.

Drill a 1/8" hole on the top of the block, right above and all the way to the sear block pin. If you drill on the center, you'll en up behind the pin. Tap the hole. (For these operations you will require carbide bit and tap, as the block is made of super hard tool steel and is unmachinable with regular bits.)
Then fill up the hole with oil, and tighten a screw into the hole. The hydraulic pressure will drive the pin out. Remove the block, cut the pin to the thickness of the receiver walls, and glue in place with epoxy.

This method works about 50% of the time, as pin lenghts and positions vary. If your drilling puts you anywhere other than at the end of the pin, this method won't work. If you determine you're SOL, then its time to break out the Dremmel cutting wheel and go at it carefully.

Good luck!