Extra gauges - what size???

[scottcorvette]

I would like to fit some extra gauges to my 454 68 C10.

I like the look of the factory setup but think I would need to change the wiring harness aswell to make it work. Is that the case?

I was thinking about getting a Sunpro retro tach either on the column or on the dash, and some VDO gauges to go in the bottom half of the gauge cluster.

I currently have the standard setup, can someone measure the bottom holes in the 7 gauge cluster so I can see if these gauges will fit into the holes. I would cut holes in the backing plate for them to mount in so they appear to be recessed into the dash.

Thanks
Scott