Speedo and fuel gauge replacement

Does your temp gauge work?

If so not the IVR

The speedo head can be removed to it's guts. Just be gentle.

I suspect you will find the outer spinny part is touching the part that is attached to your speedo needle.
Yes, they are all technical terms!

As for new parts, check classic, etc.

I see NOS guages on ebay for a reasonable price.