As far as I know, no one makes a bolt-on 2-bbl Fuel Injection system, yet (or I would purchase a pair, very quickly).
I doubt too much fuel pressure is an issue, especially if you have the 3-way fuel filter installed on car (which looks like this, and is located under the alternator).
The hoses are 5/16” with a 1/4” vapor return hose – which helps a lot with vapor-lock problems.
Your carburetor is a Holley 6280 (computer controlled) model number R40276 (based off of factory part number sticker of 4324647, as shown).
I suspect your plastic float has “sunk” or has absorbed fuel (can no longer stay above the fuel)
or you have some trash holding the needle & seat open.
What I would do first, is get a pair of line wrenches (ONLY) and remove the fuel line (yellow arrow) from the brass seat (white arrow) until disengaged. Line wrenches look like this:
If you use open end wrenches on the fuel lines, you will bugger up the fittings (that is not an "if" but a "will").
Note: you will have fuel run out of carburetor seat as well as out of fuel line. There is nothing you can do about either. The fuel will evaporate away – so no smoking or creating sparks, etc., for a while.
Next, remove the seat (should be brass, but might be steel) - the white arrow. Now you can use an end wrench, if wanted. Unscrew the seat all of the way and remove from car. The needle should be built into a cage so it can’t escape. You can use a few different mediums to clean the needle & seat (carburetor cleaner, gasoline, water, etc.). I do advise against using other chemical cleaners though.
With needle/seat inverted so the line fitting is downwards, you should be able to pour a bit of water onto the needle and it should not leak out through the line fitting. If it does, keep cleaning. If it fails again, get a carburetor kit.
If it does hold water, then dry it the best you can, reinstall it with its gasket (tightening the line last), and try to get engine to run again.
If you still see fuel leaking – then you got a bad float (aka: time for an overhaul).
Note: this has nothing to do with your fuel leak, but might with drivability concern. I made a circle (rose color) of either a broken vacuum line or a broken vacuum cap - that needs to be fixed.
BudW