The problem with the bell replacement kit is that it doesn't come with a critical piece, the pivot pin that the two blocks go on. It wears too and the best you can do is press yours out and turn it 90 degrees to expose new surfaces to the blocks.
I installed a Crown HD unit the other day and for the price, it was a huge improvement. The real u joints are smoother than the stock parts, though not replaceable if they wear out.
While it looks like it would work in a 74, The listings are 76 to 86......?
1975 CJ-6 1983 CJ-8
1986 CJ-7 Laredo 1986 TJ-7 Trail Jeep
2003 Inca Gold TJ Rubicon