920 heads

We went through about 3 sets for Bucky for his 67 Formula S. I was never sure if they were cracked or just a casting flaw. I have 2 at home, I'll check them. It will be a couple weeks till I get back home. 302's will work for you, but you will lose 20 cfm on each intake. They also have smog bosses, but on the plus side they have hard exhaust seats. 302's tend to crack between the valve seats.
I'd rather stay with the 920s since my other head is in prefect condition. These 920s heads really ROCK compaired to 675s , big improvement in power.