If I may add a couple comments here, you are probably much better off not using an old original casting. The casting process is much better now than before and aging an old casting doesn't help. That said, any casting should be pressure sealed with resin as a precaution and while the casting is new. No guarantees, but better to stack the deck in your favor.
If the intended purpose of this is to make a touring motor, OHV, you do not need a 4 port design. The older Cragar/Schoefeld/Millers were siamese port designs (2 port) and more than adequate. You will also not need a lot of compression, this in my opinion is where folks get into bottom end trouble.
Lastly, there is a dedicated monthly Banger thread on the HAMB here is the new one for Dec.
https://www.jalopyjournal.com/forum/...wered.1087920/
J