I know there was a guy who wanted to know about P&Ping his stock heads, we shunned him and didnt give him any good info.
I FINALLY found that link: http://forum.camarov6.com/showthread.php?t=46270

Does anyone have ANY info about porting stock iron heads????

I know that you want the most CFM and Velocity. People say in that link that stock heads are the most efficient I/E% at 84% I/E % efficiency. So I dont know if it is possible to improve ANY on stock heads.


thanks

 

abbott heads are better for intake, intense is the best for exhaust
its obvious that you can improve on stock head flow

I just dont wanna port too much, or port too much in one cylinder, and that cylinder runs leaner than the others...

 

I was the one who posted that on camarov6. I researched heads in general and really dove deep into researching the 3800 port jobs.

In regards to CFM and velocity, you want the largest velocity with the smallest CFM.

A good gage I use is the exhaust to intake ratio. You divide the exhaust cfm spec by the intake cfm spec and your ideal percentage should be between like 75-85%. If you fall within that range then your velocity should be at ideal for the complete air flow.

 

and yes you can make stock heads a lot better, if you can achieve a higher flowing CFM rate with the same amount of velocity then you have just increased your horsepower a ton. That is the mystery behind porting heads

 

Can you say that so that I, the rookie, can understand? How do you come up with the cfm numbers? And how do you change them?

 

The CFM #s come from putting the heads on a machine called a flowbench which measures the amount of air the heads are capable of moving through them over a given period of time.

If you know little about head porting or flow, I wouldn't dig too deep into them. I wouldn't do anything more than gasket matching if I were you. Leave the port work to a pro...

- Justin

 

i'm also gonna shave the head gasket side down about .15" to get a higher compression ratio