AFR heads can flow big numbers and make a lot of power. Trick Flow heads tend to create better velocity in the ports and have been shown to create a very wide torque curve while maintaining impressive peak numbers. Its best to match your camshaft profile to the heads. Some heads like the ones mentioned are well designed and can flow measurable amounts of air at a lower lift such as 0.0200" where as a cheaper head such as the patriot junk on ebay does not flow well until much later (particularly due to casting imperfections and valve shrouding in the chamber). You'll notice the most performance by going with a reputable shop that can build you custom camshaft profiles using YOUR specs. An off the shelf camshaft is designed for a variety of applications. It will make good power, but having the lobes profiled to enhance YOUR vehicle will make the difference. Vehicle weight, traction, transmission gear ratios, auto/manual trans, converter stall speed (auto trans), engine setup, and an honest goal of what you want are all factors a good custom cam shop will take into account. Also, I was able to get away with a solid roller camshaft for my small block with minimal maintenance. Gone are the days of solid flat tappet camshafts ticking and requiring adjustment every friday night. I checked mine every oil change and 2 or 3 rockers would be barely out of spec. I say this because hydraulic roller cams will not have the upper rpm power that a solid will make.
A heavy vehicle, tall gears, low stall converter, ect... will require a more broad powerband with a wide torque curve. Anything 351ci and under I would run either an AFR 165 head, Trick Flow 170cc twisted wedge, or Edelbrock RPM heads.
A vehicle that can get away with a sacrificing some low end and shifting the powerband upward might like AFR 185 heads, trick flows 190cc twisted wedge, or Canfield heads.
If you're building a big inch small block there are crazy amount of options but none are "budget" lol. I've had success with RHS pro action 215cc aluminum heads on a 4.125" bore 3.4" stroke small block. Racing Head Service also sells a 180cc version but be wary because the flow rates they post are based on a 4.125" bore not a 4.030" bore most common of the stock block based rebuilds. A BIG head designed for a 4.100" or 4.125" bore will see a lot of valve shrouding around the outside edge when placed over top a smaller 4.000"-4.030" bore therefor not seeing the same results.
My main point is to pick up a quality head that can perform as is and is cast with extra material for porting if plans get wilder in the future. The peak power of a motor is impressive only when the vehicle is at the exact rpm at which it makes the peak power. Investing in a custom ground cam and matching valve train will make for a stout motor that is MORE impressive up top yet seems to pull forever.
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