The 3 port Olds looks good, but reports I have seen, does not add all that much. Most guys doing the Chevrolet overhead conversion use the 2 exhaust port 1928 Chevrolet head. Google "MTFCA; poormans RAJO" or "MTFCA; Chevrolet overhead" Are you building a speedster?
The Chevrolet head is not a bolt on and go conversion it requires an adapter plate between the block and head. Unless you can make your own adapter plate or find one, you might be better off just getting one of the high compression heads. I have shared a lot of info on the Model T Ford Club of America as have others. The project has its rewards, pitfalls and takes time, YOU need to be able to figure stuff out and get it all to work together. While the cost still can come in way under a bare RAJO head, it will still cost a good deal more then a good high compression head. If and when you actually take the plunge and get started on this, there are people that can offer advice out there.
https://www.youtube.com/watch?v=hiVaPQzH9OM
https://www.youtube.com/watch?v=_p40Pd1viO4&t=18s
You might want to ask on the Model T Ford Club of America (you need to sign up but do not have to be a member to post) I think you will find more people there that have done stuff like this then here or HAMB.