You've got a real mix of stuff there. Another street car that wants to be a drag racer. I would work on the timing and timing curve first then tune that carb/intake combo. Some lash work with the cam and/or advancing the cam a bit should help too. There's a lot you could do before putting another converter in it. And it would be cheaper to send your converter in and have it upped in stall speed than to purchase a new one.
Crap, I'm going to edit this thing 5 times before I'm finished.
One of things you should understand too is that "converter stall" numbers provided by a company, even a really good one like FTI are nothing but estimates. They have no idea of what the torque level is going to be that their converter is put behind. You say your current converter is 2100, please tell me how you tested it for that number or is that the number that was provided when you purchased it? If the latter is the case, then you really don't know what your converter is currently flashing at and that is a number that you need. You also didn't mention what rear tire you're running or the weight of the vehicle. All of which can have a bearing on how the torque of the engine is handled through the converter to get the car moving.
Then I see you have this posted on clubhotrod.com too. And you got this answer which is a bit more elaborate but in the same ballpark as mine:
Assuming that the present converter is operational to slip to 2100 (as designed), it should do a pretty good job of moving your heap off the line. Your final drive ratio is 11.41:1 in first gear (3.06 X 3.73), twisting through a 27" tire (with a modicum of engine torque, you should be close to getting some daylight under the left front tire on launch). You may not realize it, but the looser you go on the converter, the farther away you move the car from being streetable and you may just as well begin yanking out the extra seats, bumpers, bumper braces, etc., etc. as well as moving the battery to the extreme right rear of the car, using #2 welding cable from the trunk to the engine bay. Drill a hole in the bumper to mount a good quality master on-off switch (required by drag rules when you remount the battery anywhere other than the stock location. In my opinion, you have a great, streetable combination now, and going looser on the converter will only wreck that.
I'm going to change lanes and suggest that you make other changes to produce additional engine torque before you opt for the looser converter. You may or may not be familiar with ported vacuum versus manifold vacuum. Ported is vacuum taken from ABOVE the throttle plate. Manifold is vacuum taken from BELOW the throttle plate. All of us old guys are familiar with using manifold vacuum because that's the only type that was available to us before the advent of the Federal Government forcing auto manufacturers to clean up their act, beginning in 1967.
What I have in mind for you is a DUI (Davis Unified Ignition) distributor, together with the best plug wires money can buy and routing them away from each other by at least a full inch from the cap to the plugs, using standoffs and/or separators that will not conduct electricity. You will provide all the facts and figures about your combination and the engineers at Performance Distributors in Memphis will dial in your new distributor before shipping it to you. YOWZA, YOWZA. (901) 396-5782. I strongly recommend purchasing direct, not through a speed shop.
He makes some good points here and I think we both are pushing the same idea. People put together combinations with some expected results and when said results do not come about - people decide that there must be something slightly amiss in the combination that we so carefully crafted. If you do this long enough, you find out that ordering parts A,B and C out of the catalog will not guarantee the result, but ordering those parts and fine tuning not only will probably get you there, it might even be a bit better. That's what this game is all about.
