3B2H/4B2H/5B2H are shaft ratings using the Maltby Playability Factor (MPF). If you go to https://www.golfworks.com, scroll to the bottom of the page and select Maltby Playability Factor you can see how the rating are determined and there is a listing of shafts and correcponding MPF. You can also enter some details about your game to get your own personal MPF by selecting Find a Golf Shaft to Match Your Game.

Save your money and get a new driver. There is no comparison between a 20 year old driver and modern technology. Not even close.

The new TSR drivers are coming out next month and would recommend that you have a look at those. Might go for a fitting and there are some awesome shafts available that will definitely go well with those new Titleist heads.
Your Titleist fitter can take good care of you. Worth taking a look at. Agree with Brock, twenty years worth of R&D makes a big difference. Best of luck and welcome to the Team Titleist site. =)

You will need to find a shop that can replace shafts on heads that old. There are many .335 tips to install. But what shaft characteristics will fit you best?
All Titleist drivers since the 910 series share the Sure-fit hosel so shafts with the adapter can be interchanged with a simple undoing a screw.
If you don’t love a 975 with the current shaft, consider upgrading. A new shaft will cost more than the retail value of the entire club.