Head flow vs power

So I just had my Blue Thunder B's rubbed on and picked up roughly 70cfm on the intake and 80cfm on the exhaust. Don't have the flow sheets in front of me yet. So lets assume if it made 650 horses before and nothing else is changed what should I roughly expect to gain?

Depends whats the rest of the combo? How many inches, what cam, how high you spinning it?

If this is the eve im thinking of i say 400hp on top what you put down all ready if all is the same with the setup. keep us updated.

If all the rest of the engine was correct and up to par, then I'd say a 150 Hp gain. However, sometimes when you improve one part, then the other part becomes the "weak link". So if your heads were greatly improved and the intake manifold and the carburator do NOT becomes the restriction in the system, then look for the 150 Hp gain.

Hope this helps,

Charlie

I figured that 100 to 150 wouldn't be out of the question. Let's assume 100. Now add boost..........................

10psi = 168hp

14psi = 195.24

18psi = 222.45

Thanks guys. I wanted to make sure I was thinking correctly. They made 1016rwhp bone stock out of the box. I'll post up pictures eventually. I just have to finish a few things up first.

Northwest outlaw wrote:If this is the eve im thinking of i say 400hp on top what you put down all ready if all is the same with the setup. keep us updated.

I have a little help when it comes to getting enough flow but my box stock heads were probably the only thing keeping my stock 2 bolt block alive for the last 3 years. Another good thing is that since my intake is now about 20lbs lighter the car might transfer weight a little better. I was amazed how much extra aluminum is included with the TFS street manifold.

Good thing I have a new A460 block. Thanks again Lem.

I've been really busy since moving so I haven't had much time to check in here but now that it's lightened up a bit I'll be on more often.

Here's my little helper.

I just finished up a project for a customer a 582 Chevy big Block engine. It had some heads that flowed 385cfm on the good ports and since it was for a jet boat application we were trying to get it to peak at between 5500 and 6000rpm. With these heads the best I could get was about 650 horsepower. The customer decided to get a new set of heads this time an AFR 335 runner piece that flows about 405cfm at the same(.700) lift. With the head swap we picked up an honest 50 horsepower at 5800rpm and a similar amount of torque at 4700rpm. Someone had really hogged out the runners on the first heads and when I checked them they were at 365cc! So by dropping 10% port volume yet picking up close to 10% flow the engine really responded. Had we been turning the engine more rpm with more cam and compression maybe the results would have been less spectacular but it's still a pretty dramatic difference and it also shows just how important velocity is when it comes to making torque and horsepower at the desired rpm for a given displacement.