Looking for some info

S&W Model 14 revolver not really used for distinguished revolver events anymore. I would like to put a full length scope rail on it. 
Any of you knowledgeable people know what rail to use that will cover the top once the front and rear sight go bye bye ?

If it's a cherry Model 14, I'd sell it and buy a new Revo that is factory drilled and tapped for a scope mount.

I like the Jack Weigand mounts.

https://www.jackweigand.com/swhpmnt.html

EGW and Leopold are nice too.

https://www.midwayusa.com/product/1018662029?pid=977812

https://www.midwayusa.com/product/1362144904?pid=144904

I second the Jack Weigand mounts.  I have used several on S&W revolvers.  They fit into the rear sight recess and use the two existing screw holes (on older models) or three on newer models.  If it is an older gun with two holes, you just need to drill and tap for the center hole which is covered by the rear sight if it is replaced (visible from underneath but who looks there).  No need to remove the front sight making it easy to restore to iron sights.