318 build up

From one source, the early 273 forged crank numbers are:
2268119 Manual trans
2463551 Auto trans
I suspect these numbers are later service replacement parts numbers, because this does not agree with this PN info which is from a FABO post for forged crank numbers:
2128278
2128869
2205700
These 3 above are probably the original forged crank PN's.

The later cast 273 crank (also used in the early 318s, I believe) was 2843699, per what I can find. But I do not know if this is the original or just a service PN.

FOR BALANCE:
I would consider using the early 273 crank and the 273/early318 rods for the following reason: If you are using the KB167 pistons, the total weight of the 273/early 318 rod plus the KB167 pin and piston, would be:

726 gr + 132 gr + 526 gr = 1384 gr

The stock 273 rod+pin+piston weight was 1479 gr for 4 bbl and 1476 gr for 2 bbl. So you would end up about 95 grams under the stock weight. Engine balancing would be easier as you would only be taking weight off of the crank, not adding it on. (And it may require less weight removal than balancing to the 318 crank, which may be cast for a heavier 318 rod+pin+piston weight combination. But I don't have the stock 318 piston weight to be sure of that.)

Now that I think about it, the later rods with a 758 gr weight, would add 32 grams to take you to around a 1416 gr total and the balance process would be even easier.

I do not know if the 1416 gr total weight is within balance limits for the 273 crank; it is 5% off from the stock 1478 gr 273 weight, so I suspect not; maybe someone can comment on this.