? Flow #'s On LT1 heads

I am just finishing up a 383 W/ a Vortech and just got some flow #'s on my LT1 heads and was wondering what everyone thinks. They were flowed before and after on the same Superflow bench. The heads ended up a 305/230 @ .700 278/216 @ .500

Very impressive peak numbers for an LT1 casting. what were the stock numbers?

Mmmm... I assume they've had alot of material added :). If that's at 28" anyway.

The stock flow #'s @ 28inch were 205/180 @ .500 & 240/185 @ .700. We didn't have to add any metal and went with 2.02 intake & 1.625 exhaust. The guy I had porting them used to work for AFR and really knows what he's doing.

Err.. LT1's simply do not have enough material to literally gain enough crossectional to flow that at 28" depression. Nothing to do with skill... They also wont get anywhere near 240cfm stock.. do you have LT4's?

These are LT1 heads. They had a slight DIY port job on these heads when I got them that was done poorly so those stock numbers are a little higher. I will have the flow sheet by the end of the week from my motor guy. Skill has everything to do with porting. There are not very many guys who know what there doing. The proof is in the flow #'s.

Skill has a great deal to do with it regarding shape and whatnot, but the bottom line is that no iteration of the LT1 casting has enough material to get that kind of crossectional out of it. Everyone has "280cfm" lt1 heads.. I've had dozens.. the best ever peaked at 264cfm on our sf600, 4.060 bore, half inch clay radius with most peaking in the 25X range. We've welded up several LT1 heads, & you won't get near that w/o adding alot of material. Sorry, good luck with it :)

SkarodoM, All I'm saying is the numbers don't lie and if you want the specifics on how we got those numbers e-mail me and will give you my engine builders phone # and I'm sure he would be more than happy to explain exactly what he did.

Nah, I've seen more than enough from people. Not trying to start another internet fight, but stuff like this doesnt do much other than help other people BS about flow numbers, as if it werent bad enough. I'm not saying you're being dishonest or anything, but I know I'm not the only one who knows an LT1 casting cannot be made to peak over 300cfm at 28" depression as-cast.

You can make over 600hp NA with that much air... so good luck with everything :)

Here is my preliminary flow sheet where the heads are flowing 298@.700, but my engine builder has since fine tuned them more and got the numbers to what I posted above. I will add the flow sheet when he sends it to me--which should be by the end of this week. Skarodom you can take it with a grain of salt, but I have no reason to lie.



Flow Numbers (http://www.angelfire.com/scifi/russthechamp/Flow_Numbers.jpg)

I dont think anyone implied you are lying. However there is simply not that much material to remove via porting and get those numbers, without bench tricks. Were those a 1993 casting?

You say I am not a liar but that is exactly what your insinuating. They are an early casting of the Lt1 heads (92 and up) I don't know the specific year they were produced (Casting Number -10128374). Your right there is not much material on the short side radius, but there is room elsewhere. He even said that with more time with the heads he could get them to flow another 10cfm. If you guys believe that you have found the absolute limit to an lt1 head than it's your loss. You know maybe just maybe sombody can port a head better than you. I don't want to get into a long drawn out fight so i guess will just leave it at the fact we agree to disagree.

No, it's being insinuated that you're simply being misled, not that you're a liar. You're the customer, you arent supposed to know this stuff offhand. Someone else already has your money, so it doesnt do anyone any good to start arguments. You posted your numbers with a question, and the bottom line is that on a superflow bench at 28" depression, those castings simply do not have enough material to literally make the hole that large. We're just talking SBC, nothing special. Even ignoring the area over the short side, if you only consider the area at the pushrod, you cannot get the crossectional out of that straight section (I use this example because skill has less to do with that area when shape and efficiency comes into play) to flow anywhere near that. Its not magic, people dont just pull 20cfm out of their asses, it's an exact science, and 300cfm wont go through that hole at 28". As far as how "good" one person is or another... There ARE a few people who can do better than we can, but you know what? None that I've come across will deal with the public. How about guys like Greg Good, or our local Chuck Riddeck? Greg is down in TX, taught the SAM cylinder head course for awhile, and now is back doing ProStock/fuel/etc. cylinder heads. He's about as close to a guru as anyone, the guy is absolutely amazing, one of the best few in the world... and even he doesn't claim any more than 280-285 peak with these castings. Chuck did a 300cfm set of LT1's.. .of course that entailed adding ALOT of material to them, along with revised valve angles (which in itself is an extremely time consuming task).

You don't seem to understand that probably 90% of auto shops lie or mislead people. Noone's calling you a liar, and you can put your head in the sand and pretend your guy is right and that's all there is to it. If I spent much $ with people I'd certainly want to believe them too. The bottom line however is that with the previously outlined conditions, an LT1 casting does not have the physical capacity to be opened up that much, much less ~315?!

Have someone else flow them... see what they say.

Hope it works well for you :)

-Phil

*chuckles at people not grasping basic concepts*

http://www.lamer.net/owned-dogs.jpg

Originally posted by got_hp?
*chuckles at people not grasping basic concepts*

http://www.lamer.net/owned-dogs.jpg

Who?

Never say something is impossible. Someone will always prove you wrong.

Originally posted by It's Cochese!
Who?

Never say something is impossible. Someone will always prove you wrong.


the idea here is that.....there is a maximum amount of air that can flow through any given size port.............a port with of size X has a physical maximum amount of air that can flow through it.................however people are claiming that they can flow more than the physical maximum.


take a hollow piece of pipe...........and lets say due to its cross-sectional area, in absolute perfect conditions it could flow 300cfm peak.

then some guy claims he made it flow 350cfm.

it just aint happening........even if you had absolute perfect skills (which no one does) .


no one is saying the guy is a liar, and im sure they will provide him with flow sheets that SAY the heads flow what they claim..............but from my understanding, it is pretty easy for a shop to make a flow bench say what they want.

Poor Phil, he's so misunderstood :(

Some people just dont get it that he's just trying to help (this isn't the first time a thread has gone this way.) He's just trying to let you know that you may wanna have the heads flow'd by an independant shop, to verify these numbers.

I'm sorry, but when someone who does this stuff for a living tells me not only that the numbers seem high, but are IMPOSSIBLE to get, that's gonna make me curious as too if i'm beeing BS'd or not.

What phil is saying is that picture the pushrod pinch area. its a perfect rectangle, so its not too tough to calculate at a 28" pressure drop what kind of flow you can get. no way can the port flow more, period.

I'll chime in too. Disclaimer: I am not a head expert. But just incase the point hasn't been made, there is no such thing as a stock (non-welded) LT1 casting flowing >300cfm. And 315 (the 305 plus the 10cfm more the guy said he could do) is getting into Dominion 32V territory.

I am certainly not calling RCF925 a liar. Just saying that I don't see how the heads could flow what he was told if the conditions were "standard". If I thought the figures were accurate, I'd be buying a set!

Rich Krause

Originally posted by rskrause
I'll chime in too. Disclaimer: I am not a head expert. But just incase the point hasn't been made, there is no such thing as a stock (non-welded) LT1 casting flowing >300cfm. And 315 (the 305 plus the 10cfm more the guy said he could do) is getting into Dominion 32V territory.

I am certainly not calling RCF925 a liar. Just saying that I don't see how the heads could flow what he was told if the conditions were "standard". If I thought the figures were accurate, I'd be buying a set!

Rich Krause

That's a lot better than calling someone a liar. Misled, perhaps, but calling someone a liar (or insinuating it) isn't warranted.

I would also be VERY curious to see an independent flow test. I'm sure we could all pitch in a few bucks. If it turns out this is true, I'd really like to get the contact of this guy.

Boy it seems like I really struck a nerve on this board. You are all so quick to call BS. obviously it's pointless for me to try an argue this because I didn't port the heads. Plus it is stupid for me to argue over the internet because everyone on here seems to know the absolute limit on Lt1 heads.

Got Hp what kind of a guy searches around on the internet for pictures of dogs screwing each other... honestly get a life.

Originally posted by RCF925


SNIP

Got Hp what kind of a guy searches around on the internet for pictures of dogs screwing each other... honestly get a life.

We may disagree on heads, but at least we agree on one thing ;)

Rich Krause

Originally posted by RCF925
Boy it seems like I really struck a nerve on this board. You are all so quick to call BS. obviously it's pointless for me to try an argue this because I didn't port the heads. Plus it is stupid for me to argue over the internet because everyone on here seems to know the absolute limit on Lt1 heads.

Got Hp what kind of a guy searches around on the internet for pictures of dogs screwing each other... honestly get a life.

I'm not calling BS. I know nothing about porting LT1 heads. However, more people than not are questioning it. Also, these same people probably would want to know that if these are accurate flow numbers, how it was done, and how to recreate it.

I am one of the latter. Perhaps you can post pics of the heads? Like I said, I am REALLY interested.

Here is my numbers
LIFT INT EHX
.100 74 69
.200 127 121
.300 191 152
.400 254 183
.500 283 192
.600 287 201

How much does it cost to flow a set of heads at an independant shop. Here it is only $35. With that, I will put up $5, come on now we only need 6 more people to toss in $5. After the heads are flowed, if they flow 300+ cfm, put me down for a set. This is just what I am looking for.

Originally posted by RCF925
Got Hp what kind of a guy searches around on the internet for pictures of dogs screwing each other... honestly get a life.


ask the guy who made the picture and operates the website, its not mine, i just used the image to inject some humor into this discussion, although your naiveness was entertaining on its own merit.


dont get your panties in a wad........no one here called you a liar, people are just simply stating that you were misled.

ill be willing to add $5 to the fund started by Black_Z to get the heads independently flowed, just for ****sandgiggles.

I talked to my engine builder and he's just about ready to do another set of LT1 heads for another customer. the flow bench he uses is another independent builder who really doesn't have a stake in this or is biased, or trying to rip somebody off. Before any of you said why don't you take them to another independent builder to get flow tested he already mentioned it to me. Since my heads are all ready on the motor he said he will have the next set he's doing flow tested on 3 different testers, 1 of which is probably someone you all would recognize ( Johnson Racing, Santa Maria, Ca.) It might be a few weeks before there done but as soon as he has the numbers I will post them.

The flown# kinda high on the LT1 heads, Most Lt1 heads flown 250-270cfm. I got mine flown at Agostino resulted 256cfm on my LT1 heads.


Bruce
93LT1 Conv w/ZF6
Blown D1-SC/N2O
ARE built 383ci/Stage II heads

There is a Pro Stock engine builder in New Orleans that has the latest and greatest flow bench (don't remember the model number). These guys port heads that flow well over 400 cfm. We brought in a set of expert-ported Brodix SUPR 23 degree aluminum heads and they flowed 295 cfm. The shop owner was very impressed - adding that he has NEVER seen a set of 23 degree small block heads flow over 310 cfm regardless of port size, so 295 was excellent.

Thunder Racing has done testing of numerous companies' "330 cfm" LS1 heads, only to find that they all flow around 280.

Think AFR 190's are good? They only flowed 233 cfm at Thunder.

AFR 210's? Not too bad, at 280 cfm.

In light of this, I've gotten to the point where I don't believe anything over 300 cfm in 23 degree SBC heads.

I HAVE seen LS1 heads flow over a true 330 cfm, but they aren't 23 degree heads, are they?

Mike

So really, let's settle the debate here (at least for me):

Same person ports the heads, is there any significant advantage over going with a different set of heads than stock?

Originally posted by engineermike
There is a Pro Stock engine builder in New Orleans that has the latest and greatest flow bench (don't remember the model number). These guys port heads that flow well over 400 cfm. We brought in a set of expert-ported Brodix SUPR 23 degree aluminum heads and they flowed 295 cfm. The shop owner was very impressed - adding that he has NEVER seen a set of 23 degree small block heads flow over 310 cfm regardless of port size, so 295 was excellent.

Thunder Racing has done testing of numerous companies' "330 cfm" LS1 heads, only to find that they all flow around 280.

Think AFR 190's are good? They only flowed 233 cfm at Thunder.

AFR 210's? Not too bad, at 280 cfm.

In light of this, I've gotten to the point where I don't believe anything over 300 cfm in 23 degree SBC heads.

I HAVE seen LS1 heads flow over a true 330 cfm, but they aren't 23 degree heads, are they?

Mike

I bought some AFR 190 heads that were ported. When I got them I flowed them and they did not have the same numbers the porter boasted about.

It was not the vendors fault, but MY porter came up with numbers a lot less. He ported them and got 278 / 216 at .600.

Based on MY experience, you HAVE to get flow numbers from a bench OTHER then the porters bench to be able to advertize their flow numbers.

In fact, the ported numbers from my engine guy were not THAT much improved over AFR's stock advertised numbers but I'm not sure as to the crediblity of the AFR #'s

Originally posted by engineermike
There is a Pro Stock engine builder in New Orleans that has the latest and greatest flow bench (don't remember the model number). These guys port heads that flow well over 400 cfm. We brought in a set of expert-ported Brodix SUPR 23 degree aluminum heads and they flowed 295 cfm. The shop owner was very impressed - adding that he has NEVER seen a set of 23 degree small block heads flow over 310 cfm regardless of port size, so 295 was excellent.

Thunder Racing has done testing of numerous companies' "330 cfm" LS1 heads, only to find that they all flow around 280.

Think AFR 190's are good? They only flowed 233 cfm at Thunder.

AFR 210's? Not too bad, at 280 cfm.

In light of this, I've gotten to the point where I don't believe anything over 300 cfm in 23 degree SBC heads.

I HAVE seen LS1 heads flow over a true 330 cfm, but they aren't 23 degree heads, are they?

Mike

Hey Phil, you think you can impress that pro stock engine builder with that set of Victor Jr's you got sitting at the shop?;)


Bobby

I think everyone here will agree that flow numbers are only a porting tool and not the definitive way to gauge performance.
There was a set of lt1 heads ported by Greg Good that appeared in the old lt1 head flow sheet ( anyone have a link to it ). I've actually talked to the guy that owned them and attempted to buy them. They peaked at 285 but had some really insane mid range numbers. That being acheived by a porting genius should shine some lite on lt1 head capabilities. If I recall correctly the car through an auto and mild solid roller put down somewhere around 420-430 rwh. on stock short block.