305 heads with 202/160
 

I need a set of heads for my 355 chevy dirt car. 202 valves are a must. I had a set of double hump with 202 valves but they have gone bad. I found a set of 305 heads with 202 valves for a really good price but I am being told that they will knock my horsepower down drastically because they do not flow good. Any ideas, suggestions, or tips for me about the 305 heads? Don