Most seem to be running the MTI stage 1 heads, but has anyone tried other heads? Not that I'm against MTI's heads, but they cost well over $2500 for stage 1 once you have LS6 cores purchased. :confused:

I'd love some feedback on this, and dyno numbers if you have them. :thumbs:

 

http://www.z06vette.com/forums/showt...threadid=43332

 

I didn't realy see much head info there, CJS. Are you suggesting the 5.3L TEA heads?

 

Stage 1&2 or the stock heads. :cheers:

 

What sort of power differences would you expect between the three? :cheers:

 

Yes, the 5.3 TEA heads have shown themselves to be a CONSISTANT performer. That post shows 420 rwhp with a 222 cam, not bad at all! I have never seen a neg. post on these. I am sure Andy's are just as good.
This is because with the CNC program at least they are uniform and this leads to their consistant performance. Unless you are paying $2400 to $2700 for top brand name hand ported heads, well it seems risky to me on what you may get for your money. I have seen many posts of lower than expected HP numbers, and I have to attribute that to the heads not being up to par. The cam is known quanity, it is what it is, so that is not the problem when this happens.

 

I've had the Stealth cam with MTI Stage 1 heads for 2 months now, and I got 405 rwhp/375rwtq, torque reaches 350 ft./lbs. at 3600 rpm and stays above that out to 6000 rpm with a very smooth torque curve. The last dyno point shows 340 ft./lbs. at 6400rpm.

These dyno numbers are SAE corrected,are thru the FLP cats and the Z06 Ti mufflers. There is a tiny tiny lope that a trained mechanic will pick up, but it otherwise sounds stock to the ordinary driver. This car is almost too quiet, I may try some ORPs to liven it up a bit!

The MTI Stage 1 heads are now 4 years old, as I had them on my '99 TA before and they made 421rwhp/401rwtq with a C2 hammer cam on that car. They are just CNC milled LS1 heads(not LS6) that MTI polishes/touches up some to sale. I looked at MTI's website and these heads are $1,995, not $2500!

I am very happy with this combo! On a recent road trip, I got 24mpg with the AC on for the whole 350 mile trip and at an average speed of 80-85 mph. With ORPs and perhaps a ported throttle body I expect to reach 420+rwhp/380+rwtq easily. It maintains the low-end power/torque of a stock C5 LS1 engine and dramatically increases the hp/tq in the mid-range to upper rpms.

Randy :cheers:

 

To the best of my knowledge, MTI does not CNC their heads. They are all hand ported which is the reason for the cost. As for the TEA heads. If you want something even less expensive look at the Patriot Performance 5.3L heads. They are $1295 with no core exchange required. As for TEA, look at Phils recent "re-port" of his TEA's which fixed some "issues" they had. MTI does good work, and they stand behind thie work. IF the cost of the Ls6 heads is kicking you then consider the 5.3L head. You get the compression without milling the heads. The core cost is lower, and they can be made to flow right along with an Ls6 head. The LS6 is just a bit better. But the 5.3 is close.


[Modified by J-Rod, 11:53 AM 8/28/2003]

 

J-Rod, you are correct! MTI today does not use CNC heads these days, and the head porter that they use to send their Stage 2 heads (back in 1999 and 2000) to now works for them. All of their stage 1,2, &3 LS1/LS6 heads are hand ported under his direction. :cheers:

Randy

 

Thanks to all!

2 questions:
1) What is better, CNC/machine built heads like TEA or hand ported heads (assuming a competent porter) and why? I know the latter costs far more...is it generally worth it?

2) So the MTI stage 1 heads are simply a ported 99-2003 LS1 head? Would there be any advantage to starting with LS6 heads, or does the MTI work make both fairly equal in the end? I keep hearing tuners say it's better to begin with LS6 heads. :confused:

 

BTW: How much higher did MTI raise the idle with tuning for the stealth cam? The video on their page made it sound like it was idling quite a bit higher than stock???

 

I'm not sure what they flow, but if you're looking for some good heads (from what I've heard), you may want to give Andy at A&A a call. He's a forum vendor, and I think that his stage 1's were $999, and his stage 2 might have been $1500. It's worth a call, and Andy knows his stuff! Good Luck!

 

You have to be careful what you are calling stage one and stage 2. There are no set guidlines to define these. You need to look at flow numbers. My GTP stage 1s flow as well as other vendors stage 2s. I'm not saying go get GTP I'm just saying look at the flow numbers.

 

Does anyone have a good source of head flow numbers?

How did you guys narrow it down to one set when you purchased?

 

I think in general if your searching for max hp, then the hand-ported heads offer you the opportunity to go for it. If your looking for more modest gains, then the Stage 1's and CNC milled heads offer a lot of bang for the buck. I would expect on my setup that stock LS6 heads would give an additional 15 hp raising up to 420rwhp, and that stage 2 LS6 heads would go 15 hp above that to 435rwhp or more. Stock LS6 heads flow more than Stock LS1 heads, there's no debate there.

Whether hand porting is worth it or not depends on how far you think your going to mod your car. If your just looking for modest performance, then probably not.

I think J-Rod compiled a spreadsheet of head flows, maybe he can provide a link to it. It should help you decide what you want.

Randy

 

Jayson tuned my car and kept the stock idle rpms. He had no need to raise it.
Not sure why it sounds that way on the audio clip?

Randy

 

Randy, would you agree that it DOES sound pretty high in the clip? Or is it just me? :lol:

 

Can anyone find alink to this spreadsheet?

 

I realize that choices are made according to funds available. I had a decent size budget so I purchased Z06 heads fully assembled. I will end up not using the springs or retainers since I went to a custom grind on the cam. I looked over the heads very carefully and noticed that each port pocket was exactly a perfect duplicate casting. So with this knowlege I knew that it is impossible to hand grind each port to an exact match. Yes they do layout each port with dychem and scribe marks, but human hands are not close to perfect with a power tool in them. Probably pretty close. But Im sure on the other hand, you could get the very small details by hand porting whereas it would be impossible to reach it with a 5 axis CNC mill. The solution and best of both worlds is to have them CNCed and then hand finished. I'm sure that most of the vendors here are quite competent on porting heads. I chose LPE to do my porting because they do have a name....I can't wait to get them back and do the install.


[Modified by Scubanme, 7:04 AM 8/30/2003]

 

I think you'll be very happy with the LPE heads (the ones from LPE, not the GM CNC head). The LPE stage I heads have great low lift numbers. Cleaning up the CNC marks by hand (stageII) picks up about 7-10 cfm. I think you will be quite happy with the LPE heads.

As for my spreadsheet. I am in the process of re-working it.