They (well, contractors) are re-engineering the F-1B as well: http://arstechnica.com/science/2013/04/new-f-1b-rocket-engine-upgrades-apollo-era-deisgn-with-1-8m

They (well, contractors) are re-engineering the F-1B as well: http://arstechnica.com/science/2013/04/new-f-1b-rocket-engine-upgrades-apollo-era-deisgn-with-1-8m-lbs-of-thrust/ http://arstechnica.com/science/2013/04/new-f-1b-rocket-engin...