Hello Doc Larry,
I noted with great interest the photo of the "LA" fitted with the Detroit model "6-71" engine, you ask wether she has now got to much horse for the cart. NO not at all, that wonderful "CASE" transmission would stand the power from that engine with no problems at all !!
That backend is in my opinion an engineering masterpiece capable of most anything you could throw at it - typical case design and engineering.
Did you know that Deere & Co in the mid 1950's purchased an "LAI" new and fitted it with a "3-71" Detroit, and used it to test the traction capabilities of the extra power delivered etc etc. I have seen a very recent photo of that very tractor taken at a tractor show in 2006 at Penfold, Illinois, U.S.A, but have mislaid it's designation number given to it by Deere test engineers. Nice to see such a historic tractor has been preserved fotr future generations.
Alan T. Lewis