Again flow #'s mean arent everything. There is a lot more to heads then that. I used to think the samething.
I think you should have head the heads milled some took the compression upto 13-14:1 and changed from the 850HP to a 950. put a dart or victor intake on it. The hurricane I am sure was a decent intake but when all is correct that intake wont be in the ball park of other's.
Example 383 in a Mustang 2 I owned for a few months. Afr 220's, 13.5:1,victor jr intake, 645lift cam, bg 875 carb, conv was 5800 just a spare I had from my dragster it was close but not right. It weighed 2750lbs with me in it 14x32 tires. It ran 6.0's & 9.6's.