4 inch Truck Stack with a normal I.D. of 3.870

would that be close to the stock Nomad exhaust muffler tip.

[VulcanE]

I don't know the exact measurements of the stock muffler, but the stock muffler WILL slide inside a V & H muffler (slightly less than 4" OD, and slightly more than 3.85" ID) with some room to spare.