Mike
It depends , the roller cams will make more power if they are solid rollers , the hyd rollers are really not a big advantage but to me a solid roller is too much expense & too finiky for daily street use .
With street roller type specs using a solid flat tappet cam we are making around 400 RWHP on a Mustang dyno which reads to lowest so to me you are way down on power by 150-200 hp , & we are using iron production 915 or 516 heads & a Holley street dom intake .converted gross number are 630 hp & 730 Ft lbs .
Your compression will be a bit lower using alum heads , the super stealths should increase air flow & a single plane intake may help although I have had good results from the RPM so that is not the first place I would look .
Why did they stop the dyno run @ 5100 was the powr falling off already ? If so this is probably carb related , peak power should be 5600 shifting at 6000
The cam I normally use is the Lunati TF 60 / Tf 57 ground on a 110 Cl , you will find the lobe spec on pg 185 in their online catalog