That topic was beaten to death 20 years ago. Not even worth discussing.

 

(Clicked wrong button, rest of this post is under "Spoiler")
I appreciate everyone's input on this thread. I understand that doing more than just a cam would result in greater performance gains. I guess what I'm basically chasing is to match or exceed the stock LS6 power output with factory like reliability. I will look into some 243 heads for the car as recommended, might as well do everything at once if cost isn't going to be drastically more.

 

CamMotion will happily grind a custom cam for you. Just tell them what your intended use is, what performance level, etc. they know what to ask. Great company.

BTW, 243 heads are worth it. I’m also on the fence about porting for a mild cam street driver. With the 243s, mild cam, and headers it should put out near 400 whp, or about 450-470 crank horsepower, depending on who you believe for drivetrain loss. I think that’s pretty stout without going broke.

 

We've had a local machine shop put a 5 angle valve job on the heads and a back cut on the intake valves. The valves were the standard valves not the sodium filled 02-04 Z06 valves. The work helps low lift flow and gives a bit more torque. Porting will naturally depend on who does the work, how much work they do and the owner's goals vs. going with aftermarket castings.

A 6spd LS1 04 GTO with a stock airbox, SLP full exhaust, 243s, Summit 226/234 turned 400/400 hot after a dozen pulls figuring out a dip in the power band.

 

Headers too?

 

SLP headers and loud mouth

 

I should also ask. Is this with the stock clutch? I would imagine the stock clutch should hold up fine with anything around the high 300s-low 400s horsepower since the factory LS6 puts out about around that? A heads and Cam upgrade isn't as radical output wise as forced induction.

 

I have a stock GM LS7 replacement clutch because my slave cylinder died before I ever did engine mods.

You might want to avoid clutch dumps, lol, but should be fine otherwise.

 

Yeah I don't launch the car or do burnouts, the transaxle gives bad wheel hop even at stock power. Just for cruising around and quick rips down an open road like I said. I also think it should be fine. How do you like the LS7 clutch? I know it's a popular upgrade that's supposed to feel close to stock? I've driven some aftermarket twin disc clutches that felt like on/off switches. Great for dumping the clutch at the strip, not so great for daily driving.

 

Yup, exactly how I drive mine too.

The LS7 clutch feels just like normal/stock. Although it started out for the 505hp C6 Z06, I think this is pretty much the standard clutch now for anything from 1997 forward.

Hang onto this link in case you ever decide/need to change it out. Scoggin Dickey has been a Chevy dealer for about 90 years and carries a huge inventory of GM performance parts. You can count on genuine stuff and they have a good staff to help.

https://sdparts.com/i-23179965-sdpc-...-flywheel.html

 

There is some good info above and some questionable suggestions IMO. Which we know how opinions go, mine included. None the less, here we go....

Adding LT headers to an otherwise stock car is mostly a waste of money unless your primary goal is improved exhaust note. The gains will be minimal without doing heads, cam and x-pipe. And the added cost of a tune for LTs only makes LTs a terrible single mod for the money..

Cam grinds are like fake ***** you buy your girlfriend. You always wish you went a size up. The 224 to 228 grinds are good street drivers. I've ran the 228r myself. But, so can 232/236 cams (which I run now) with the right tune, and much better with a gear swap. 3.90 or 4.11 (the 4.11 being the cats *** with high revving cams). I've run both with both cams and the 232/236 loves a 4.11. The 228r liked the 3.90 more with a few hundred less rpm to redline.

Stock 243 heads are better than as cast 241's, but a well ported set of 241s can put out much more power than stock 243s. And in turn well ported 243s will out produce well ported 241s. You already have the 241s so the question is do you port the 241s for more power (30 to 40 more whp) than stock 243s, or do you spend $700 on 243s for 15 to 20whp? Depends on who's doing the port work and their going rate in 2025. Otherwise aftermarket heads are more easy to source, produce well documented power (so you know what you're getting) but not as cheap as port work typically (which also isn't "cheap" when done by a reputable machinest.

I ran the LS7 clutch with stock flywheel for like 2 years. I didn't like it, but others, as mentioned above, like it. I think it makes the car feel lazy. A Centerforce or other DF clutch with a lightweight aluminum flywheel is my preference. The revs come up much quicker. Takes some getting used to compared to that "stock feel" but there is no comparison from a performance perspective.

Here is one of my dyno sheets with the 228r, ported 241s by WCCH (back in 2003), and short tube BBK headers. With 3.90s my car was a blast to drive until I blew it up. Especially after replacing the "LS7 clutch" with a Centerforce DF.




Shortly after smoking cylinder 7 on that build I went with the 232/236/113+2 custom grind from Cammotion. Coupled with 4.11s and Kooks 1 7/8s and offroad x-pipe the car was a fun NA screamer at 418whp. That was on stock '99 injectors. It made 428rwhp with stock '01 injectors. (Ignor the sporadic lines on the printout, the tuner, Bill from 2nd Street Speed in Perkasie PA, was having issues with his graphs printing).



The peak power difference between the two cams was minimal. And after adding the Kooks LTs and off-road x-pipe I gained 28rwhp. Which is why I am suggesting above that LTs only is a big fat waste of money unless sound is your primary goal.

I hope that long winded response is helpful.

PS...if you want a stock like drive that is like Jekyll when cruising around and goes on a murderous rampage when in the throttle like Hyde...go straight to a supercharger.

Or....do it all and then you'll really be happy for the life of ownership.

 

How are you going to inspect the lifters unless you first pull the heads??