I understand that the speedometershop does nice work and has been around for a long time. I have never used them but some friends have.

You should also contact Classic Instuments that was mentioned and see what they could do. They will modify existing gauages as well. I used their 5 inch guages in my 52 and the fit perfectly. They have great customer service. The new oil sender in the kit was defective I called them and the sent a new one out the same day. No questions asked. I had it the next day.

In my 54 I am in the process of rebuilding them and putting a volt meter in the housing in place of the ammeter. Everything will be 12 volts.