I recently took apart an untouched '96 300. I learned a few things that will help with the build of older engines.

1. On the spacer plate, that sits between engine and trans, there was a foam ring to secure the rear main, or to give an extra seal. I like that.

2. The tiny efi starter is great for engines where the headers/exhaust trap a conventional starter.

3. The efi engines have added slats or rails for the oil pan. They sit on the mounting surface of the oil pan, one on either side, and distribute the bolt pressure evenly.

4. I was always told to put a bit of sealant around the keeper for the harmonic balancer, on the crank. But I was surprised to see oem sealant on the leading edge of the h.b. that slides through the seal.

 

Those little upgrades are good to know! Things that Ford felt were necessary, but didn't think of until later.
I particularly like the idea of the oil pan and valve cover rails. I need a set for my new engine.

 

Yes, the pan rails upgrade is a great addition. I was impressed with the foam ring on the spacer plate to back up or seal the rear main seal. But that is only because I seem to be leaking a bit there.