Well, since I first posted, I purchased that Troy, MO 1968 122 (130) with the tachpod and lower dashpad. I'll probably use that as a guide after I pick it up and when I get back upgrading the 220.

Agent_Strangelove was nice enough to sell me a radio blanking plate as well as provide me some photos and measurements for the late-style knobs and indicators.

As of today, I've drilled most of the holes and mocked up the switches, knobs, and, indicators. my self-built and covered dashpad looks ok, but hardly original. It will work, costs way less than $300.00 and looks not too bad, but I certainly made some errors.

So I wanted to spare some of the dashpad-building experiences in case any of you are considering this yourselves.

1) there are two commonly available canned foam options for building your own dashpad. Both come from the local home store and come as expanding (gaps and cracks) and non-expanding (windows and doors). The former does indeed expand, sticks to metal (but not permanently) and is a beige/white color. The later type does not expand sticks to metal and paint quite permanently, and is a yellow in color. Most importantly, the yellow foam is softer, will not "sand" very well and seems to be prone to voids, and warping if you remove it from the surface you sprayed it on.

My advice here is that if you are building a pad from scratch, use the expanding (gaps and cracks) stuff only!!!

2) Do not spray the yellow stuff directly on any painted metal. It bonds permanently and will not come back off without a serious fight. My top pad was sprayed right over the metal, and I deeply regret it... The white stuff sticks, but will come off cleaner and with much less trouble. It also warps less if you use a plastic or tape mask over your surface. BTW, I recommend blue painters tape under the foam.

3) When cured, you can cut the foam with a knife and the foam shapes ok, but the yellow stuff balls up under a coarse sanding, while the white shapes well. The end result with the yellow stuff is a bit rough and feels a bit uneven despite care. Sanding is absolutely necessary to get a smooth surface under your final upholstery.

4) Upholstery. I used a rubbery black shelf liner material when recovered my original pad. It stretched and folded ok and looked fine. Sadly it's no longer available. I settled for somewhat=stretchy black Naugahyde similar in color and texture to the material that the stock grab handles are covered in. It sells for about $15.00 a yard (it's plenty wide, so you don't need much). Trouble is, the stuff is not as stretchy as you'd like and it resists the high quality ($11.00 a can) 3M adhesive spray. Sure you can get it to bond to the foam, but you have to clamp it and that permanently crushes the foam. Plus if you want to "pillow" the covering, it does not behave right at all. It's especially troubling on the ends where you have to cut and glue the fabric to itself. That just does not work all that well.

This issue became a critical failure when I tried to cover my knee pad. The stuff was just to rigid, inflexible, adhesive-resistant to make a proper lower pad. I plan to try that part again after I get my '68 home.

My final conclusion/recommendations are these:
1 Mask off the surface to be foamed with blue painters tape.
2 Use the expanding-type foam only
3 Find a nice-looking but very stretchy covering material