Auto to manual tranny

[68Timber]

The TH400 in my military Blazer has got to go. Nothing wrong with it except lack of overdrive. I wouldn't mind swapping in a five speed, maybe a NV3500 or NV4500LD. I know where I can get the clutch pedal assembly, but it's manual, not hydraulic. Is it hard to convert, or even possible? I may stick with the original plan, a 700R4. But while it's down for the turbo install I may go manual if it's not too extensive. Honestly, I don't even know if the NV3500 or 4500 will bolt up to my transfer case without modification. As you can tell, I don't know squat about auto to manual swaps. If anyone can shed some light on it I'd appreciate it.