Motorcraft carb on 258 engine

It takes a little work to get the things put on by the factory hooked up correctly and working correctly.  That translates into the vacuum lines. They must be correct. If not all you are doing is fooling yourself.
That said. I have never had a problem with either the BBD or the YF carburetor other than they are too small in the first place.  The BBD is 194cfm.  The engine can happily use something up to the almost 400 cfm range.
If what you want to do is strip out the vacuum lines because you have no clue how to re-do them, don't do it half way, get rid of them all. The Electronic feed back on the BBD can be unplugged but before you do that center the metering rod in it's motion.
By the time you screw around with getting parts to fit and linkages to work correctly and you can eventually you also may very well spend as much money as is required to pick up a used 4bbl manifold and a Holly 390 or a Carter AFB 400 or a 500 CFM Holley 2bbl.
A 2100 Autolight will work with an adapter and some creativity.  But it too is still smaller than the engine can use.
A nutter bypass works.  I have not bothered with it, as far as I am concerned it is a half way solution to a bigger problem and not done completely it is not a total solution.
But then again.
If your engine or car must be smogged, be sure you know how to tune it so it can be.
Just saying.

Better yet, here's a link to the PDF file that comes with the eBay guy's carbs:

Actually a 258 cu in engine can justify the use of something closer to 373 cfm depending on the rpm used to determine what is a viable option.  And a 400 cfm Carter or Edelbrock AFB is a beautiful option.

I ran a Holley 390 for a while on a Jeep J-10, 258, Clifford intake, four speed. It ran great, but felt like it could have used a little more carb -- and that was with a stock cam! The only other mod was a 2" exhaust with turbo muffler (no cat). The 390 is a great economy/power compromise, but for all out power you need a little more.

Remember, you can't directly compare 1V/2V cfm with 4V cfm! 1V/2V carbs are measured at 3" of manifold vacuum at WOT. A 4V carb won't maintain 3" at WOT, so engineers cut it in half and rated 4V carbs at 1.5". To compare, convert a two-barrel rating into a four-barrel rating by dividing the two-barrel rating by 1.414. To convert the four-barrel rating to a two-barrel rating, multiply the four-barrel rating by 1.414. So the 287 cfm 1.08 MC2100 is comparable to a 203 cfm 4V.

The 258 is generally good for up to a 500 cfm 4V, which would be a 707 cfm 2V. That is with a better cam/intake/exhaust. The original 2V BBD carb is generally rated at 195 cfm (the only references I've found), equivalent to a 138 cfm 4V. The 390 4V is equal to a 550 cfm 2V. Some racers run the 500 cfm Holley 2V, but you'd get better throttle response and low speed operation with the 390 4V due to the smaller barrels (and only using two of them at low speeds, which increases charge velocity).

That's the one on Jeeps. Try one off a Dodge 318 early 70s vintage. :)