I bought a 99 m6 t/a from my friend.He tells me he believed that the heads were ported by the previous owner.The heads are stamped on the front facing the radiator with the words CNC 1892.Can someone tell me if these words and #'s mean anything.The car has headers and a Borla exhaust.But the car seems just to quick for just a exhaust mod.

 

cnc is a heads porting company. Only way you can check is if you go back to the original owner or get it dynoed. If you ask the owner, he may know the flow numbers. Stage 1, or stage 2. On a stock motor heads don't help a whole lot, the stock ls1 heads are pretty impressive. The time they shine is when you get a more drastic cam.

 

I can't get ahold of the original owner that did the mods. So what are some dyno #'s that my car should put down to the rear tires with headers and Borla cat-back exhaust.I'll take it to either the track or dyno in 2 weeks and I'll see the horsepower this car has.If the car has head work than what is the minimum horsepower gain over the exhaust mod to the rear tires?

 

what type of headers, lt, mids, shorties. Usualy a heads an cam car will put at least 400 rwhp.

 

They are shorties or mids.The idle is a little choppy so it may even have a cam in it.If it does have a cam,headwork,mids,cat-back exhaust than is 400 rwhp power a good conservative # that I should see?

 

I don't know about conservative but if you do get the car dynoed and it's making anywhere near 400rwhp (380+) then the car definitely has some internal mods.


CNC isn't just a company. Any company (TEA, GTP, LPE, etc...) can sell you CNC-ported heads if they used a CNC machine to port them, most do.

 

there ya go.

 

Since you know the number, call CNC in FL and ask them. All of our heads are serial numbered, stamped, and all of the data on them is catalogued... so if you see anything with the prefix Ai on it...

Really, you could always pop the intake off and take a peek. I believe alot of other guys sell CNC'd stuff as machined b/c it looks pretty & the general public goes for that.

-Phil

 

Thanks alot SkarodoM. I called CNC but the guy I need to talk to is not in on the weekends.I'm going away for a week on vacation tomm. So I'll try them when I get back.

 

So did you ever find out if they were CNC ported?

 

Wow this is a old thread. Yes my heads were mildly ported by CNC.