I also have a 1930 Chevy and found there is a tremendous need for replacement heads.
Who makes heads for model Ts? I need to reach out to some experienced head makers to get more insight on getting some Chevy heads made.
Search "model t Z head"
There is a guy in Maine making them.
will reach out to him.
I assume you are looking for some one to cast new iron 6 cylinder OHV heads. I trust you have plans to buy something like 25 heads. If that is the case I can probably point you to a top quality highly skilled iron foundry
Since Chevys are OHV and OHV heads are much more complicated than the flatheads mostly used on Model T's, you may first talk with someone who makes OHV heads.. Mark Chaffin in California makes repro RAJO OHV heads for Model T's. Here's a thread where he discusses the effort involved (including a contact e-mail) http://www.mtfca.com/discus/messages/80257/92268.html?1243038489
Chaffin's heads are made of aluminium - cast iron may be better but is a lot of more trouble, so the cost would raise. Kevin Prus makes a high compression flathead for T's in both alu and iron, he may have some advice on cast iron head production? You can find him in this thread: (click on his name to send a personal message) http://www.mtfca.com/discus/messages/506218/516398.html?1423361658
Here's another thread with more cast iron castings discussed: http://www.mtfca.com/discus/messages/331880/409043.html?1387416461
I have a parts dealer interested in a 50 unit order if we can get a price car owners would buy at.