Gotta ask you a couple of questions first. Do you already have one or more of these intakes, or do you have to buy any one of them when you replace it? If building a 73 340, you might want to go with the earlier pistons and cam. 73's were lower compression and cam was a little different too. If your planning on going much over 5000rpm often, then you might look for a set of aftermarket heads. But just for a warmed over decent running 340, the factory ones will do fine. What do you plan on doing with it after the rebuild- daily driving with occasions of spirited driving, weekend warrior, or strictly a strip car with occasional street excursions? The cost of a rebuild for basically the same engine, earlier spec 340 vs. the 73 version should be close. The earlier parts should give you more bang for your buck tho. Just don't go too overboard.
On a basic stock rebuild, I'd use the LD340 if you can buy it reasonable, and modify it to fit the Thermoquad. If you really want performance then go with an air gap and Holley of your choice, with larger cam. The LD340 was a great intake to begin with, and for street driving, it is a great piece.
If you want to go a little faster, then you might want to get a junkyard 360 engine and go with a stroker version/kit for it. No need to go with a forged crank unless you want to go much over 450-500 HP. Cast cranks should last on a street car without too many problems. Just make sure your oiling system is up to par if you go that route.
Let us know what you decide.