Perhaps a better question would be to ask how much air they flow. What's the CFM rating on these heads and then compare that to the CFM on the heads you have or the heads you are considering buying. Then you will be comparing apples to apples. HP numbers are dependent on too many other factors to attribute any gains to one particular part.
If you're going to compare CFM numbers, you better make sure they were checked the same way. On the same equipment would be the best.
What part of the country are you in? Just out for fun or do you want to be competitive? If you're trying to be serious, the 3.0 class is pretty serious almost anywhere in the U.S. IMO, you'd be wise to bolt a set of these heads to your truck.
If you're into learning, build your setup with OE-based heads, strap it on a dyno and let 'r rip. Tear it down, strap on the waglers and redo the dyno tuning sessions and see if your peak and area under the curve increase. I predict they'd both be considerably higher, especially the area under the curve above 5000rpm. :thumb: