Worthwhile upgrades to stock '73 340?

Not sure if I mentioned it, but according to the previous owner everything was rebuilt 5k miles ago, but 10-12 years ago... Stock rebuild only, so new rings, bearings, and stuff. The The inside is fairly clean. The cylinders walls look in great shape. The reason for buying the engine was not to do a full rebuild. He said it ran great 10 years ago... So I kind of wanted to replace the needed parts and worthwhile upgrades. I am not in a big hurry, so I can spread things out a bit. This is a winter project to swap motors...

I am going to ask around to the "car" people I know. There are tons of shops to choose from in the metro Detroit area...