Does anybody out there in C3 land know whats the best way to remove build sheet from top of gas tank without taking it all the way out?

Fixed for ya !

If you plan on actually finding the build sheet there, the best way would be to drop the tank completely. There will be less chance of damaging the sheet this way.
If you get the tank out, and the sheet is really stuck, you could at least take a good quality photo of it, and leave it stuck to the tank, or at least have evidence/proof that it did come off of your car, in case it gets torn.
Just my opinion.

If you don't have a service manual for your car, I'll try to give a few tips on tank removal.

First, you have to remove the spare tire and tub. Drain as much fuel as you can from the tank before starting.
Once the tire tub is out, you will see the crossmember that the tank sits on at the front of the tank. On either end, there are two bolts that hold the c-member to the frame. The nuts for these bolts are on the inside of the frame, but there are holes in the frame there so you can get a wrench on them. Take two of these bolts out(one on each side) completely, and loosen the other two.

Then, at the rear of the tank area, you will see two bolts that hold the tank straps to the frame. You will need to remove these bolts all the way. They are fairly long, so it might take a while to get them out.
You will need to unbolt the exhaust hangers on both sides, too, unless you have sidepipes. The exhaust has to be dropped for the tank to spin/tilt out.

Disconnect all of the fuel lines from the top sides of the tank, and the bottom pick-up. Have a drain pan ready, and be sure it's large enough to hold however much fuel is left in the tank. Once you have the lower fuel hose off the sender unit, you can plug it off, so it won't continue to drip. Remove the two electrical connections from the sender unit.

Once the rear bolts are out, the exhaust is dropped, the tank empty, and the fuel lines are all off, you can remove the two other bolts holding the crossmember. Be sure to have a helper, or a jack under the tank before taking the last bolt out of the crossmember. The tank will have to be tilted toward the front of the car to get it out. It takes a little playing with, but it will come out.

I'm sure there are some things I forgot here, but this is pretty much the basics. Hope this helps, and I hope you get your build sheet!! If ya do, be sure to post a pic of it for us! Adams' Apple2007-01-10 19:49:22

I know this post is a month old, but if you haven't got the build sheet yet I will try to find an article that I saw in an old Corvette Fever a while back that details a procedure to remove and preserve the build sheet. But it will take a little time because I'm in the middle of a move and my old mags are packed away somewhere. Let me know if you want it.