1964 Dart Owner - In Over My Head

All the currently-available manifolds are from China, but they are not all alike. As you can see, the Dorman item is more expensive than the "same" manifold from other companies. The reason is simple, you (don't) get what you (don't) pay for. Dorman's the high bidder, so they get the first-rate manifolds from the foundry: cast correctly, no core shift or other flaws, little or no excessive casting flash that gets in the way of your installing the manifold, etc. Other marketing companies bid less, so they get the 2nd-rate parts (you don't want). Still others bid even less, so they get the 3rd-rate parts (you really don't want), and so on and on down the line.

It's a bitter pill to swallow, but buying the good one avoids cursing yourself for having failed to do so. Your options:

Buy a used one: spend less money, but you have to hope you get one that isn't warped, cracked, or otherwise faulty. Hope it stays that way.

Buy a cheaper-than-Dorman new one: spend middle money, but you have to contend with relatively poor casting quality and accuracy. Makes it a pain to install, too.

Buy a Dorman new one: spend more money, but "done in one" and you can move on to thinking about things other than exhaust manifolds.

As for the choke pocket: Yes, it's different on any new manifold you can buy today. So's the heat riser valve. Don't worry about it—it'll just require a № 1231 Electric choke kit.