If your determined to get a tunnel ram, I know a guy on this site that has a used wieand and two 600 holleys for sale.
You could always sell your demon.
750's will be way over carbed for your combo.
I do agree the single plane vic jr may be the way to go and use your 750.
PM me if you really want to go tunnel ram and I will get you to the person that is selling his.