Our boat is 50' with 3/8 BBB chain 11,000 lb breaking strength. ( wanted to switch to G4 but a problem getting a new gypsy )

Going by the photo (table 1) which seems reasonable I should be concerned. According to the table you take the 30 knot wind speed and multiply it by a factor of 4 for 60 knots of wind. (this is assuming you're bow to the wind with a minimum windage boat.) that 60 knot figure is 6,400 lbs of pull on the chain. With a higher windage boat that's sheering in a 60 knot wind the chain is close to if not at or above breaking strength of 11,000 lbs. That would make me think about using the engine above 50 knots if nothing more than keeping the anchor from breaking free.

Good thing I have my FX85 Fortress with 1" rode as a storm anchor. We've been in 50 knots at anchor holding well with the 88lb Delta (actually it drug very slowly during an 8 hour period. Dragged 20 feet). The sheering was what scared me. We have quite a bit of sheer with a lot of wind because of our high freeboard. We have a riding sail that helps but not much.