All Ford's V10 requires 5W20, Even the early ones. Ford started with 5W30 and in 2003 released new specifications for all v10's. The reason, in the effort for increased fuel economy, Ford uses Low tension rings on all of the v10 pistons, they can allow a 30w oil to pass causing oil consumption. FYI I have 110,000 miles on mine, I always use a motorcraft filter, I did use a Mobile 1 filter but it cause the timing chain to rattle on startup. the Motorcraft filter, for whatever reason, stopped the startup noise.
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