I finally had my GTP stage 2 LT4 heads flowed by a local shop. I never did get any info with the heads from GTP and now I know why. I'll let the numbers speak for themselves.

lift int. ex.
.200 126 111
.300 183 139
.400 222 178
.500 253 191
.600 272 201
.700 272 204

Head info- 207cc intake, 77cc exhaust, 56.8cc chamber, 2.02 intake valve, 1.58 exhaust valve.

Needless to say I'm very upset about the intake flow numbers. I paid $1200 for LT4 heads and another $2gs for porting to get a head that flows less than a stock ported LT1 casting. I will be calling GTP to see if they care to rectify the situation. If not I will most likely send them to Ai and see what kind of magic they can perform for me. Does anyone have the contact info for GTP? I can't seem to find it. Thanks.

EDIT: These were flowed at less than the industry standard 28" of water. All the numbers seem to be where the should be at 28", what a relief...
I had them reflowed properly and the numbers are as follows

lift intake exhaust
.050 36.5 30.2
.100 73.0 60.4
.150 109.6 90.6
.200 146.1 120.8
.250 175.8 138.4
.300 205.1 153.9
.350 225.6 166.9
.400 245.9 179.4
.450 259.4 192.5
.500 270.0 204.9
.550 279.8 211.0
.600 288.5 214.8
.650 295.3 216.5
.700 298.7 218.4

 

My L.E. ported iron heads with stock valves flow about the same. 255/185 at .500. I paid $200 for the cores off ebay and $700 for the port job, springs, milling, etc. Sorry you got ripped. Good luck rectifying the situation. It's sad to see all these businesses lately screwing people over.

 

Before you get too crazy on GTP you might want to get all the specifics about the bench and it's setup and get someone who knows flow benches to "analyze" that information. Flow benches are kinda like Dynos in that they can be "made" to skew the numbers very easily (pipe diameter, preperation etc), sometimes not intentional, and well, sometimes intentional I'm sure. This local shop wasn't by chance thinking that they could get some "work" out of you, were they?

You could also call up or email GTP. I seem to remember Craig saying that they keep their flow numbers from all the heads they do. Then maybe you can compare apples to apples flow bench setups.

http://gtp-racing.com/
GTP Site

http://gtp-racing.com/contact_us.htm
Contact Page.

Seems that there are no constants anymore when everyone only cares about some number on a piece of paper. Don't get me wrong, I'm guilty too, but just seems the only way to truely evaluate something is to dyno a before and after (same day, same dyno) or get all the tuning done and compare track numbers. Even then it is subjective to the rest of the system, especially the tuning.

Frustrating.

 

Wile does have a point, but I personally like GTP for head porting as much as I like ARE for building engines (If you didn't get my point, I hate both).

I know of many how had their GTP heads flowed and were not off by a little but by a very large amount. Best example I can think of is Cody (97RedSS).

 

Yeah, I remembered that story. Was defianatly a bum deal.

I really believe that Craig Gallant is a world class head porter. I also really believe that there is no way on god's green earth that he can personally port the demand he must get. So... I have to also really believe that with GTP you are paying for the name of Craig Gallant even though you probably wont have him porting your heads.

I wasn't trying to stick up for GTP necessarily (although I do have a set of GTP ported heads and it saddens me to think that my numbers might suck too, although I don't believe that they do ). All I was saying is that it is hard to hang a company on something as subjective as this topic.

Maybe it is deserved though, and maybe it will cut the demand for GTP porting unless you want a mega thousand dollar porting job that Craig might actually have a hand in.

As always just FWIW .

{edited to fix my smiley} :P

 

my GTP stage 3's flow in the 290's, for the record.

Something to note: they advertise 280in and 210ex for stage 2's... your's are close man. If you're going to be mad about a 7 cfm difference, you'll be really mad when you get taken for a whole lot more!

 

Yeah - Craig has the personal ability to get a set of heads rockin. However, actions speak louder than words in this business. I don't know if they just stopped caring or what but their heads have sucked for the past few years. I got some GTP "Stage II" LT1 castings a while back. After having them flowed I sold them (250s at .600).

Good luck, Larry.
Ryan

 

They do advertise that, but for LT1 heads... he's got LT4 heads, which flow 35cfm+ more than LT1 heads from the start. They don't advertise LT4 flow numbers on their site, but you'd expect them to do better than the LT1 heads... otherwise, why bother with expensive LT4 heads if the end results are going to be the same?

 

yup, lets chalk that one up as an error in comprehension on Jesse's part. If I were you, I guess I would have expect 300+ as well.

Have you talked to Craig about this?

 

Wile2K, I understand where you are coming from and I normally don't race numbers. I went to the local shop specifically because they are very experienced and know exactly what they are doing. I asked them about finishing up some work on a single plane intake I have waiting for these heads. They honestly informed me that they could do it, although since they had never done one before for an LTx, I would be better off with someone with experience in the matter to save some coin. Stand up shop IMO. My postion is that I paid for a level of flow that I did not receive. Sure, the head could make good power. But if all I wanted was "good" power I wouldn't have dropped the dime to have the "best". Like I said, I will be in contact with GTP and if they don't make it right I will send them to another vendor. It would be a pretty good showcase for a porter to eek more flow out of the "almighty" GTP LT4s. This single plane conversion is not going on until these heads flow what they should, it would be a waste of my time and money. BTW, thanks for the contact info.

 

NP on the contact info, and I can definatly understand the frustration, I'm sure I would be too. Best of luck getting it resolved, I hope they do ya right.

 

You guys are correct..I have met Craig in person and he is a very good guy and he does know his stuff. I believe they have fudged there numbers at one point in time because most people have alot more cfm on their bench for some reason

Cody

 

My LT4 GTP S2 heads supposedly flowed 296cfm (i)and 220cfm (e) corrected @204cc intake runner but I never had them flowed nor do I really care as long as the cars runs well. I also only dynoed 351rwhp NA and 535rwhp on a 150 wet shot. My dyno numbers say I shouldn't be running the times I do but the track numbers speak for themselves. When I bought my combo from GTP I told Craig everything I wanted to do to the car and he said he would port and match a cam up for my goals. I am pretty happy with my results. If I were you I would give Craig a call and see what he says about it. Let us know what he says.

Good Luck on the combo,

Matt

 

My GTP LT4's are working pretty good I think

best E.T 8.96

best mph 159.64

 

Chris, we're gonna need to know more about your setup. With your site unfinished, i'm kinda feeling a little unsatisfied

post a few details if you will.