67STRIPES

iTrader: (2)

.400 Lift flow numbers are very important for low mid and high rpm Power and torque . The valve or port is only at peak flow once per cycle and twice at .400 or lower.

Jessica brings up a very good point about the 4.125 fixture not applying to a LS1 . Its very possible that the low lift numbers would not look as good on a 3.99-4.03 fixture.

The bottom line is great improvement and great work for a home ported head. I would love to put my name on that work however, If your looking for max power go buy a set of heads done or a aftermarket set. If you want to do stuff yourself which I certainly do he has a GREAT START

Jessica

Actually it doesn't..... I've never seen a head with just more low lift flow make more low end TQ!

PEOPLE NEED TO START READING PHYSICS BOOKS AND THINKING RATHER THAN LISTENING TO "GURUS" and OLD FARTS WHO HAVE HAD THEIR HEAD IN THE SAND FOR 40 YEARS!

Makes me wonder how I can even deal with some guys.....

Jes

Rapin'Ya

iTrader: (1)

How many powerful combinations do you have out their running on succesful combinations??

A blower head/turbo head doesnt need flow as much as it needs port shape to make it run well. That is part of the physics that you can't explain in cylinder head porting. Can you even name sections of a port successfully? Yes, im testing your knowledge. Don't cheap and use your favorite Google feature either.

405HP_Z06

iTrader: (11)

Now it gets good......Rapin'Ya, if you only knew.

airflowdevelop

I'm not sure who Jessica is...but I would like to see how much top end she really has

I have played w/ an ls head here or there... and the points she is making are right on point! if you are concerned about good flow under .200... you are LOST! think for a second... what is the piston doing at that point! even UNDER .400... worry about .400 - .400 ...over the top. look at what the piston is doing then!

Old SStroker

Isn't the piston is still rising toward TDC on most cams @ .200 valvelift? Wouldn't great flow there help push air back into the intake manifold?

Speaking of GREAT low lift flow, how about a head that flows 4+CFM at ZERO lift! Bet you could sell that sucker (pun intended) to the LLIWIA (Low Lift Is Where It's At) guys. Just imagine the low rpm torque....yep you probably would need to imagine it because there wouldn't be much there.

Now don't laugh. Heads like that are out there in LS Land. I feel sorry for the guys that pay good money for them.

Sid447

Can I ask here,

The GMPP CNC'd LS6 heads.............

http://www.sdparts.com/product/88958...ccChamber.aspx

Anybody tried them, or know if they are in fact a good buy?

Rapin'Ya

iTrader: (1)

I know the person that designed the port. For the money, yes they are a very good head.

Rapin'Ya

iTrader: (1)

Do you sit behind a computer and design ports via CAD?

I only ask because I know a guy like that and the other person that ports heads by hand at this place WIPES HIS *** with R&D work and continually makes more power then a CAD dude.

Jessica

I think we have a case of SAMitis here.... think you know everything and everyone and make sure you tell us that when you get backed into a corner. Does Casey really want you throwing his name around? A lot of people know he did the GMPP port for Lingenfelter. The best part is who you DON'T know, that's what really makes this conversation funny.

As for the blower/turbo deal, it has to do with viscosity of the fluid. Blower/Turbos add denisity to the mix.....

In terms of the sections of the port.... I'm guessing you also need the diagram for a female anatomy as well? I'm going to have a problem with the port thing most likely because your going to want Pushrod "Pinch" instead of Restriction etc... I will tell you one thing that your .200" number being big has to do with valve size, throat percentage and top cut angle being wrong for the application.

Burt Reynolds up there added some good things to this discussion, maybe you need to think about what him and airflowdevelopment said.

Jes

Cliff

iTrader: (19)

If you could, measure with a set of calipers the radius of the seat from the 12 to 6 clock position and from the 3 to the 9 clock position. Also measure inside the bowl at the same positions and then where the valve stem merges from the bowl. There is a specific formula needed for these areas to have a correct venture curve with the correct seat angles into the bowl. Which makes good flow numbers without backing up and high velocity numbers. Your basic porting looks good but your missing several ticks to get the extra edge for flow numbers. If you want to pm me with this information that fine or just post it back here and maybe I can help.

airflowdevelop

No... I am not a CAD guy...

but bring both of your friends along... I will wipe both there A$$'s.

98cherrySS

iTrader: (2)

Why would you wipe their a$$'s??? Isn't that really just doing them a favor?

Hmmm...

ItsNotStock

iTrader: (24)

Please don't ruin a perfectly good thread with sophomoric bickering. You all could learn alot from each-other if you stopped the "who's dick is bigger" contest and in turn help the unenlightened such as myself and the lurkers on head flow. Thank you.

novaflash2002

iTrader: (51)

you seem to know your stuff very well, from what it appears, his loss of flow comes from changing the port design. it doesnt always help just going to town taking out as much material as you can. the theorys with the .200 and .400 lift numbers have some truth, but if you dont have a continuous flow that accelerates into the cylender correctly those go out the window.

Sid447

Agree with "ItsNotStock,"

Please can we overlook the differences and get something constructive going.
'airflowdevelop,' 'Jessica' and 'Old SStroker' & 'Rapin Ya'.........

Please don't give up and walk away. Everybody's got their say, please can we at least 'hear' it.

I'm planning for instance to go with the GMPP CNC'd heads.
But am concerned that the intake runners are actually 250cc, as I felt this might be too big for my needs & don't want to lose the low and mid-range I have fought hard to get from this tin-box I've got.
I'm also unsure of which chamber size to go for, though have a fair idea.

I want the LS6 assemblies because of the lightweight valves. I don't care about going for maximum valve size, hp or who's best and who's not.
I believe GMPP won't turn out a bad product so that's good enough for me.

Jessica

The LS6 heads are good because of the port shape design.... almost every aftermarket 15° head is modled after them.

There are some LS6 CNC programs that are pretty killer out there, only thing is your not going to pay low dollar prices for them!

They have more than just SOME truth.... until you understand what is actually going on in there your not going to get it.

Jes

novaflash2002

iTrader: (51)

WOW such bold words for some one who could not even show you how a bench flow works. Lets put it this way. I Port heads professionaly, and i have a bunch of people all over the U.S. asking me to do more for them. I fully understand and get it. Dont tell people that you have to understand the physics about it, i fully understand, i more than likely understand physics better than you ever will. (I used to teach it). this thread was about the heads not how you want to look intelegent because you can read something and sound like you know something about it, but when it came down to doing it, id dont think that you would have the slightest idea. O and where in here did you say what was wrong with this gentlemens heads? I never found it.

Sid447

These seem to promise good flow for a street car,

without the intake port being anywhere near as large in volume as the GMPP CNC'd head.

Anyone know much about these:

https://ls1tech.com/forums/new-produ...ad-option.html

Jessica,

I'm happy to pay good money for a good product, but want what's best for my needs without the sales pitch getting in the way.
Or having to pay good money and not getting a good product for what's wanted.
I also want good quality, good standard and no fitting issues.
I'm happy to pass on the killer deals and discounts, as long as it's for the right decision.

redtail2426

iTrader: (10)

well i will mess with the head some more,probably do another port a little differently.On the port pictured i did some experimentation on the valve angles and found that it can cause air/fuel seperation,which doesnt show up on the flow bench,but its not good for power.The next port will be larger,removing the swirl ramp and opening the runner a little more to maybe 220cc instead of the 210 i just did.After that i will mess with the short turn radius to see if i can find anything there.The 853 head i am working with has some real bad core shift with the valve seats,so it makes it a little difficult to get it the way i want.I just did an lt1 head that gained almost 50 cfm at .500. with minimal valve deshrouding.