If you did a write up that would be great Lilnuts.
I've been thinking of doing this for a while myself.
I've got the guages to swap in and I've compared the 2 wiring diagrams myself so I know which wires "should" go where.... but I know that might not actually be exactly be correct once I do it.
My question to you is, which tach wire did you use? The CTO?
Where did you find it, do you have any pictures of that wire and it's location?
1996 E350 XLT E | 280K and gone
2003 E350 XLT club 190k