Markings on stock throttle body? Size?

The stock TB is 60 MM. The 95-01 V8 Explorer had a 65 MM unit that will fit with a few modifications. You will need a new TB spacer to match the TB to the upper manifold. Putting a bigger TB and then restricting the flow by using the stock spacer defeats the purpose of having a larger TB.

See http://www.veryuseful.com/mustang/tech/engine/ConvertingExplorer65mmTB.pdf for the how to do it.