Hey guys, first of all, let me tell you that I am not very knowledgable on engines. So don't be too harsh on me.
My question is: let's say you are porting and polishing the stock LT1 heads without getting into any valve job. How will all that air flow in if you don't get bigger valves? I know the smoothness that you get by porting and polishing will give some horsepower, but without getting bigger valves, will you see more than, let's say, 20-30hp? Please correct me if I am wrong, I am here to learn. Thanks.

 

I've seen a flow chart of home ported heads with stock valves that flow in the 260 cfm. This gives around 80 hp difference if we assume the stock flow 220 cfm if everything matches properly.

 

i answered this in your other thread, but basically

stock heads do not max out the stock valves

porting/polishing (if done properly) will increase the velocity of the air............faster flow, means more air = more power.