1952-59 Ford 1956 gauge panel to other years?

Will a 1956 gauge cluster fit in a 1955 dash. I would like the extra gauges/holes.

 

No, but you could swap out the entire dashboard.

 

Along the same lines, will a 55/56 Mercury dash bolt into a 55/56 Ford?

I want to say yes but have never held a Mercury part....

 

This is what I did in my '55 but be warned you will also need to change out the dash end caps and modify the vertical garnish mouldings that run from the end caps to the headliner garnish moulding as well. I have pictures in my album here:
http://www.jalopyjournal.com/forum/media/albums/1956-dash-install.43963/

 

My interior is already painted and I do not want to redo it. I was hoping to install more gauges without major surgery. Does any body have or know of a gauge that fits in the hole where the heater controls go?

 

Check out Speedhut, that's what meknow63 is using in his 55. I have their GPS speedo in my 56 and am very happy with the performance.