Purchased this a few weeks ago, Car has long tubes no cats, Flowmaster Cat back I believe. 4:10 rear gears, M6. The previous owner passed away and the wife sold it to me so I couldn't get specifics. He had a lot of paperwork of past maintenance. I did not see anything about a cam. What makes me suspicious that it might have one is the Dyno #'s. After he installed the long tubes he had it dynoed : 344.7 HP, 353.9 TQ Heads have the standard 241 stamp. I thought this was a little high for just long tubes and a tune. Thoughts? Here is a video of it when I first took it out for a test drive.
https://photos.app.goo.gl/EgYrfx5Vy7qYJNMo7

 

too much back ground noise to hear anything engine related in your vid. try it again on a nice quiet back road..

 

I can see an LS1 Dyno at 344 with those upgrades without a cam. My 2002 put down 326 HP with just a lid and cat back.

 

~345rwhp sounds about right for an M6 LS1 with LTs/ORY, some minor bolt-ons (lid, catback, etc.) and a good dyno tune. Especially for an '01-'02 car with an LS6 intake, or if an LS6 intake was added.

You list a 2000 NBM M6 SS in your signature...is that the car in question? I ask because you mentioned 241 heads. Only a small amount of very late 2000 model year cars came with 241 heads (otherwise it would have been 853), so if the build date on this car isn't at a very end of the '00 model year then those are not the original heads. However, if the car is actually a 2001-02, then it would certainly have come stock with 241s.

Either way, the sound quality of the video was very poor but it doesn't sound like it has a cam to me (and if it does, it's very small). Sounds stock from what I can tell, other than the exhaust obviously being louder with the headers + ORY + catback.

If it had a cam (plus all the usual stuff that goes with) I would expect RWHP numbers, for an M6 car, to be more like ~370-380+ depending on the size of the cam. 345rwhp would be a bit low unless it was something like an LS6 cam, which is only a very small upgrade.

FWIW, my A4 '00 car made ~360rwhp with a 221°//.558" cam plus headers/ORY, air lid, catback, tuning. And that was an unlocked auto, which always dynos lower (all else being equal).

 

I've personally seen 6 spd cars do as much as 350 rwhp with long tubes only on my Dyno jet. I'm going to say you don't have a cam.

 

Witnessed several stock to the air filter 01-02 M6 LS1 f-body cars make ~325 to 326 whp on a DynoJet. Long tube headers and & good tune ~345 whp is very doable with the stock cam.

 

Yes the 2000 is the car in question.
Build date is Nov 99
I just thought the numbers were a little high for stock.... So 241 heads on mine with my build date, they must not be the original heads?

 

Will do, might uncover it later this evening and take another video. If not for sure this weekend.

 

That's definitely too early for 241 heads from the factory. For reference, my '00 car was built in May of 2000 and it still had 853s (and I bought that car brand new). It was really just the tail end of 2000 model year cars that came with 241s. With an 11/99 build date, I don't see how those heads could be original to that car. It's possible that the entire engine was swapped at some point though, so the heads might be original to that block and might never have been removed or modified. Do you have paperwork going back to the beginning for this car? If paperwork was saved, seems like there should be some record of a job that big. Again, with those power numbers I don't think the car has any cam upgrade or head work done. So they are probably virgin 241s, which wouldn't make sense to swap over unless they just came as part of a complete engine swap.

Does the car have an LS6 intake (no EGR port)?

 

You are 100% correct! I took out the file the previous owner's wife gave me and did some careful reading. I found a receipt from Prestige Chevrolet in Michigan "under warranty" it states: Heavy engine repair, 20 hours inspected rattle noise from the engine on startup. " Replaced Eng. Assembly due to int fault" This was done May 2001
The previous owner was also a GM employee in Michigan for over 30 years.

 

Makes perfect sense then; by May of '01 any warranty replacement LS1 would have had 241s on it. But they would have needed to swap over the original LS1 intake with the EGR provision to keep it emissions compliant for the '00 model year. Unless someone added an LS6 intake when they did the headers (this is quite common, as most folks delete the EGR when doing headers anyway).

 

EGR is plugged he had emissions deleted when he had the headers put in . Appears to be original intake.