First time I've heard about regear! What does that entail?
You need to know what gear ratios are in your differentials now, and what tire size you're going to ultimately end up with. And also what your engine is capable of.
Your '76 most likely came with 3.50 gears, but 4.11's were still an option at the time, so "could" be there as well. Not to mention literally 40 years of previous owners that could have swapped out at some point as well.
A stock engine can't lug down in a Bronco-like vehicle on the highway like a modern car (or even a truck!) can. It just doesn't develop the torque to pull it along through the air at highway speed headwinds at 1900 rpm!
Even a gear and tire combo that are matched well for the street and a non-overdrive trans, might not work well with your engine and an overdrive trans.
An EFI equipped engine, or one with a cam and headers and a good tune, will work differently under those conditions than one with a carb and a stock cam and exhaust.
Changing the gears involves parts and labor to the tune of about $500 at a minimum (if you can find used or super cheap parts and labor) to about $1200 for new in an urban area where shop rates are double that of a more rural area.
If you do go down this road, don't let anyone talk you into lockers or limited-slip diffs, or anything fancy. It's not an off-road truck, so you don't need the added cost, complexity and hassle of some of those setups.
Let us know what you know about yours and we can talk you through some of the better combinations to run.
Good luck.
Paul