I have a set of Curtis's 18* Big Duke Oval ports. On a litlle 522ci its at 1050hp at 7400rpm. with a brodix cast intake and a single 1250. In my books ITS WORTH IT!!!. My bosses 600ci w/ 14* sonnys dart heads was only at 1100hp with 2 carbs!!!!!. Now take and add another 100ci to my motor and I think you can do the math as the potental of the RFD heads. After I am done doing some changes I am actually shooting for that 1075-1100 w/ the same ci. Not all head guys are as honest and straight forward as Curtis. I've talked to some in the past and half are full of BS.
It takes ALOT of effort to get BIG numbers out a conv. style head. I think you'll have more coin invested in conv. heads as compared to a spread port for the same amount of money.
I would'nt go any where else except RFD. Like sonnys (not impressed).