[Pampered-Z]

Originally Posted by Shownomercy

Flow numbers aren't always what you should focus on...

True, but we are talking stock ported heads, not comparing aftermarket heads. The flow numbers will give you some idea of how much work was done to the heads. If you want to compare heads on paper to make your selection, without having to bolt them all onto the same engine and run dyno results, then looking at the flow numbers is certainly the best place to start.

If you’re porting stock heads and one set flows 175 and the other 195 it is certainly going to help you decide which might be better for your application. You want them to match the rest of the engine so you maintain the proper velocity. What good is a stage III head that can flow 210+ if the rest of the internals can't? You could actually end up hurting your performance thru the RPM range.

But we're taking a 600HP Nitrous engine build here, unlike a N/A engine the exhaust side of the head work is going to be a factor, just as much as the cam selection. Looking at the exhaust side is just as important as the intake; with Nitrous you need a bit more exhaust flow that means either more flow at the ports, and a bit more duration on the exhaust lobe. If I was ordering a set of heads or talking to the person doing the porting I certainly would want to know what flow numbers he's getting.