I have a Colt Match Target Lightweight w/ 16" bbl.  I am thinking about buying a stripped flattop upper receiver and installing it on my Colt.  Now, What kind of tools do I need for a job like this and how do I perform the headspacing?  I know this should be in a dif. forum but this is the only one getting used.  If you have a long answer please E-Mail me.  Please help!!! I'll just get it all wrong if you don't help me!

I don't know about all the tools to build up a stripped upper, but know you'll need a barrel wrench and a vice block for the reciever. I think you'll need a torque wrench too. The headspace on AR's is self contained in the barrel/bolt, that is, the bolt locks into the barrel extension, not the receiver. If you reuse your existing bolt and barrel, headspace will be exactly what it was when you disassembled the old upper.

Build it yourself is getting some more action these days... ask there and I'll bet you get good response.