I have a 1985 F150 with the 351 W. My shop manuals say it needs 6 quarts of oil with a filter change. That's what I put in it. The dipstick reads at least an inch over the full mark!

Here are a couple of things I came up with:
1. Previous owner took out factory dipstick/tube replaced it with the wrong one.
2. Original oil pan taken out and replaced with the wrong (smaller) one.
3. Dipstick not accurate.
4. I need to drain it down to 5 quarts ASAP!

Any ideas?

Thanks!