Head Flow Numbers

[V10 MOJO]

Ive looked and researched all over and i see flow numbers from 240-310cfm for head upgrades. prices are also vastly different, sometimes a thousand or so difference between tuners yet flow numbers the same.

whats the best flow possible on gen II heads?? whats stock gen II flow

 

[Anthony - 98 GTS]

Gen II stock at .600 lift is 232 CFM @ 28".

I have [******] CNC heads that flow 310 CFM - which is about max. Beyond that you start to get some real weak spots.

I think the best I've seen is 315 CFM.

 

[Martin D]

We just had my heads on the bench. They were just under 290 at .600, and flowed well all the way up to .800. No sign of reversion. They were hand ported by Brad at [******] 2+ years ago. They ROCK. But remember, it is not all about gross flow numbers.

Regards,

 

[99 R/T 10]

Quick question, when the head are worked on and valves are oversized, are the valves Viper specific or are they a common valve?

 

[Torquemonster]

310 is right up there. The TNT heads by Greg look like fantastic workmanship - what their flow rate vs velocity is compared to others I have no idea, but they are sure pretty.

Velocity is as important as flow - but you will be lucky to find anyone that can give you those figures... people only want to know the flow.

For 2V heads - bigger is not always better - except in the bar over a beer. On the track - best combo and driver wins. A daily driven street engine will not even get close to the power limit a 300cfm head COULD make so the highest number becomes academic unless they also have the best velocity around 0.300 to 0.400" lift.

I'm hoping to get some custom 40V heads done for my future TT project and those babies will flow some serious air - way beyond what is possible with factory 2V castings, but that's another story...

 

[jp]

I use Fererra chevy valves in my heads. (0.100 longer stems)

Quick question, when the head are worked on and valves are oversized, are the valves Viper specific or are they a common valve?

 

[Fast Freddy]

personally i would go with a cnc port jump versus hand porting. it is hard to beat a computer when porting for flow and velocity in my opinion

 

[Vipermed 97.01]

personally i would go with a cnc port jump versus hand porting. it is hard to beat a computer when porting for flow and velocity in my opinion

that is very true provided that the original programing was specd to perfection.Thje cnc is only as good as the program and programmer.once perfection is FINALLY accomplished then you will have a winning product

 

[Daniel Cragin/DC Performance Inc]

The low lift numbers are very important on a street motor
with a limited rpm range. We have flowed many a head that reportedly had 300cfm on the intake but have never seen it.
Just as important as flow is reliability, you need good valve seats with a proper press and the correct spring pressure.
Budget heads can make power but you will pay on the back end if you loose a seat, break a production valve tip or have to replace lifters every year.

 

[Ron]

What kind of power increase does a good porting job produce on our GENII engines?

I know there isn't a direct correlation between flow and HP, (too many other variables) but in general what would it do all by itself?

What is the range of costs for same? (porting only, not R&R)

Thanks...

 

[Martin D]

As for spring pressure - how does 195 on the seat and 520 open sound?

 

[utahviper]

That sounds very strong. I think mine were 130-135 on the seat and 375ish open.

 

[Ulysses]

What kind of power increase does a good porting job produce on our GENII engines?

I'ld like to know this too.

Also, how do you determine what flow and velocity is needed for your setup?

Thanks.

 

[Martin D]

Hey Utah....that sounds about right. I just went over the top on my cam. But, the car is unfricking believable now.

 

[Anthony - 98 GTS]

Hey Utah....that sounds about right. I just went over the top on my cam. But, the car is unfricking believable now.

Martin,

Is your car done?? Post up some numbers or shoot me a PM.

 

[V10 MOJO]

well as for my heads; ill post info and numbers after i do florida as i want to run em first before bragging starts

 

[V10 MOJO]

i will say this; greg good cannot be beat, period. now i just gotta learn how to drive so as to do his works of art justice by kickin asp

 

[Jerry Colpitts]

I AM SENDING MY CAR DOWN TO SEAN ROE OF ROE RACING TO DO THE HEADS ON MY CAR. WINTER PROJECT AND YES HE IS ALSO DOING HIS OWN HEADS WITH SOME IMPRESSIVE #S SHOULD BE GREAT WITH MY SUPERCHARGER. I CANT WAIT TO GET IT BACK AND IT HASNT EVEN LEFT YET COUPLE MORE DAYS.