to add to wallys suggestion, yer torching of the tube while still attached to the motor would not only fire-clean the tube, but most likely the whole motor!

the tube
will come out w/ persuasion to overcome its 47 year habit of holdin on
to change the windshield, the best way is to slice the rubber face off the outside [which should be replaced anyway], push the glass out from inside, then follow the steps in the shop manual to install the new one - it's also possible to push out the old one w/ rubber still attached if rubber's in good shape, but will almost surely break the glass if it's not already - sit on seat, place feet against center of glass - push hard!
sounds like you need to make the #1 best investment for these trucks - get a repro shop manual - they've got good pics w/ step by steps of lots of procedures, and we can rarely explain it as well
Bill