Is it a Special 360 ?

I myself would do the following;
(Based in your description in your post.)

Take the Offenhauser intake and cut it up. Use it as fishing weights. Even the OE intake is better IMO than the dual port. The Edelbrock Performer is approx. the same performance as the OE intake.

For an excellent all around intake, my vote based on actual useage is the Edelbrock RPM or the air gap RPM. The air gap just takes some time to warm up in cold weather and if it gets really cold, it can be a cranky intake. So the regular RPM would be it for year round use.

When rebuilding the engine, I would look at ether the Sealed Power Hyperutecic H116CP piston and ring package. It works out cheaper than separate purchases of each part. They come with a coated skirt, zero deckable and have generous valve reliefs for big lift cams should you go there in the future. Do not zero deck the piston with iron heads and small cams such as the 268 you mentioned.

Do the math and achieve a compression ratio of NO more than 9.5-1.

Speaking of cams, that XE268 is a most excellent street cam. IMO, do not use the OE 340 cam. The upgraded performance version is a nice one with the similar advertised duration and lift as the OE cam but is a larger one when you look at the duration @ .050 numbers. It is also a very good performer.

The head work you describe is a great step in the right direction performance wise. Opinions vary to OE head useage these days. I say go for it f the expense is reasonable. Also judge the performance abilty vs. a new head. There's nothing wrong with the OE head. It is just a cost vs. performance value that to many people split hairs on.
I just don't always buy into it.