Updating my pack from 1.6.4 to 1.7.10

[ariecos]

I've gone through all the mods, found their updated versions, downloaded them, compiled them into a new folder, and tested it (by adding the mods to the vanilla MC launcher) and fixed the Enchantment ID conflicts that popped up. But upon trying to load my old 1.6.4 world, the game crashed. Of course it did the "Your modded world is pre-update. Would you like to try to update?" yadda yadda yadda. Hit yes. Crash. So I tried changing things up. I moved over to the FTB Launcher and modified a Direwolf20 pack (Because my pack is kind of a mix between Attack of the BTeam and Direwolf) and I finally got it to load. Except the block ID's were all messed up and nothing spawned in as it should, my inventory was gone, my chests were absolutely destroyed, ect ect. Does anyone have any idea how to make this transition smoother and not lose everything I've worked so hard to attain? Or should I just give up and make a new world?

[plowmanplow]

There's really no practical way to go from a 1.6.4 world to a 1.7.10 world when there are a lot of mods involved.

[ariecos]

That's what I was afraid of.