[Toivo]

I use them.
I don't know what you want me to tell you though.
The engine I put them on in no way resembles a stock engine, I didn't do a 'before and after' comparison of performance.
They bolted on and seem to be working just fine.
Because they're aluminum, I went with a 10.6:1 CR.
Also because they're aluminum, I had inserts put in over the head bolt holes (steel) to give a crush-resistant, flat surface to torque against.
You should also realize that the exhaust ports are raised slightly in comparison to GT heads, though I believe they're about the same as CJ heads. When ordering headers, work with a knowledgable supplier and stress that you are using Edelbrock heads.
That's about it. I've heard differing opinions about the valve springs Edelbrock supplies with its heads. Seem to work. But I built for torque, not HP, so I don't rev that high. Your situation may be different.