Ive used cylinder heads from CHEVY,TRICKFLOW ,world products, AFR, CANFIELD and BRODIX,DART,EDELBROCK,MOPAR PERFORMANCE, and IVE inspected dozens of other brands of heads, the quality of some of the brands I didn,t list was good, many were obviously machined by less than well skilled machinists.
the quality of the castings, the thickness, and design of the castings, and the machine work done to them means a great deal, none of the Chinese import heads look like they have their act together yet, in my opinion. TRICKFLOW, CANFIELD, PROFILER ,AFR and BRODIX have impressed me the most,CHEVY,,DART, & EDELBROCK,make a decent cylinder head.
summit, jegs ,doug Herbert, are usually re-branded heads, sometimes good, sometimes less than ideal.
KEEP IN MIND you GENERALLY want the SMALLEST CROSS SECTIONAL PORT that will FLOW ABOUT 10%-15% MORE at the MAX CAM LIFT YOU WILL USE to support the horsepower levels your trying to maintain, the threads in the links below will help, but keep firmly in mind the idea of the weakest link in the chain determines the max strength, or put another way a port that flows 280cfm at .700 lift is meaningless if your cam only has .550 lift or your intake only flows 240cfm, and selecting components that are designed to produce most of your power curve at 5000rpm-7600rpm will be almost useless if you gear the car to spend most of its time in the 1500rpm-5500rpm band and install it in a car with an auto trans that shifts at something like 5700rpm, everything in the engine design should match the intended power band and air flow in the intended power band requirements, when parts are selected