Thanks for the picture David, however, i don`t think I can get one the big to fit  in my `69.

would think they had the same cubby hole in the 69. try looking in pep boys, autozone, etc. as they do make generic tanks that are different sizes. maybe you can find one that will fit.

Some 70's had an expansion tank in the system, mounted behind the right front tire.  That was different from the coolant recovery tank shown in the picture.  Most modern cars have a cooant recovery tank, so you should be able to find one that you can mount.  Be sure the pick up tube goes to the bottom of the tank.  Your car should only drizzle a little coolant if it is over-full, and then should never leak again.  Maybe you just need a new radiator cap.  

larry, the tank that is in the picture was used on 74-78 vettes. they changed the design a little bit for 78-82. also the tank in the pic is mounted on the back of the right front tire wheel well. that is a brand new replacement tank.
don't know what tank you have seen.