Originally Posted by vinniekq2
A really good example is porting on F E heads. want to wake up a 390,port the exhaust uncork the exhaust system.Old dodge sb...port exhaust side.
want to make power with vortec heads,open the exhaust.
best after market heads have a high exhaust ratio.
dont want to use a split duration cam or thumper cam,port the exhaust
how many high powered cars have small exhaust?
porting the exhaust does help, so you'd be a fool not to do it if you're searching for max power, but it doesn't help as much as the intake.
You're making sweeping presumptions that really have no basis. And there's not a damn thing wrong with a split pattern cam or even a reverse split pattern cam- the cam should match the application and that means almost NEVER using the same lobes on the intake and exhaust.
If you have to pick a side to spend your time on spend it on the intake. And a very well ported set of Vortecs with a stock valve will pick up 30-40cfm on the intake at about .550" lift. Properly built that can mean about 60hp.
And I am NOT saying porting the exhaust won't help too, if you can they should both be done. It is just not as significant as the intake.