I used the recent new comer ...the "Retro-Sound" unit.
This one is set up for Chevy AD dashboards 47-53.
No cutting was required.
The pics below are the 51 panel I'm doing right now.
(Yes, that's lizard skin on the dash!)
The knobs are infinitely adjustable and can be independent of
the head if necessary. Has SD card slot, two iPod inputs, and a USB slot on
a slick little dongle that can be mounted out of the way or under the dash.
240 watts by itself or you can add a separate amp for more power.
Squire
http://gallery.me.com/squire001#100127