So I have an 03 auto with long tube headers w/ X pipe and vararam air intake. I just acquired a set of 243 heads and I am looking for a cam for the upgrade. My NA goal is 500 to the wheel and I just had my transmission upgraded to handle the power. I have looked at summit 8720, sloppy, and BTR stage 2. Not sure since I don’t have a manual.

 

500whp is not happening with stock 243 heads and an ls6 intake.

 

500 @CRANK would be difficult, unless you are willing to give up a lot of drivability......

 

It's also not happening NA on a 346ci motor. Guys hitting the 500rwhp number in LSs are 408s and 416s at a minimum. The 346 bored to 383 are on average seeing 445-470rwhp.

Typically you'll see average 465 whp out of an LS6 with heads, Fast intake and cam NA. Typical LS1 heads and cam average around 425 at the wheels NA.

I've done a few heads cam LS1 builds with West Coast Cylinder Heads "Stage 2 -241 heads" which bench flow test out performed my stock 243s. One build (228/228/112 cam, Blackwing intake) maxed 398rwhp/389rwtq, the other 418rwhp/398rwtq(same cam, heads intake with Longtubes), and the final (232/236/113-fully forged and a Vararam) 428rwhp/408rwtq.

The first build with BBK shorties and the 2nd and 3rd with Kooks Longtubes and off road Xpipe.

Best way to get at or above 500whp on an LS1 is FI. I put a Novi 1500 on my forged 346 with 232/236/113 cam & more port work to the heads and picked up another 215 HP to the wheels. Car current state is 643rwhp/568rwtq.

So my point is...if 400rwhp is your goal you can do that easily with heads/cam on 346. If you want 500rwhp start with an LS3 or go forced induction.

 

It can be done with a stock cube ls1 with a manual, doubtful with an auto. But it will be expensive. You need to come up with a better idea of what you want out of the car instead of just focusing on a number.

here’s a thread about how to approach 500whp with an ls1.

https://ls1tech.com/forums/generatio...heads-cam.html

 

Lets see 500rwhp with an automatic works out to about 625cHP. As noted above, the only way to get there with a n/a setup is most likely with a LS3 stroker or a LS7 based engine. Just to give you a for instance, GMPP sell a wet sump LS7 engine based on the Gen V Camaro Z28 engine at makes 570cHP with a somewhat mid camshaft. Long tubes and a FAST intake will get you a bit more power. Other than that your looking at a crate engine from say BluePrint engines and those sometimes come with iron vs aluminum blocks

https://www.chevrolet.com/performanc...s/ls/ls427-570
https://blueprintengines.com/product...am-psls4272ctf

But your stock transmission, differential and possibly axles will not live long behind such a beast, so you will have to budget replaces for those as well, so you are talking about $25K total plus labor.

 

Well thank you for the info and I’m not ignorant to the fact that I may have to upgrade the TB and intake. I am surprised to hear 500 HP to the wheel is where drivability starts to suffer. But I’d rather see a big high plateau or a steady one then cry about a particular number that doesn’t win me any awards.

 

N/A drivability starts to suffer quite a bit shy of 500whp!! 500whp is at least 585hp@crank!! At the 585hp mark, you are almost 250hp over the 1hp/cubic inch plateau!!!!! I'm not saying it can't be done. But to have decent street manners, and a somewhat reliable engine, it's just not feasible, unless you go FI.......

 

I can agree. I just purchased a '97 with an LQ9 swap, LS2 TB, LS6 intake and 243 heads, ported and polished. The block was bored to 6.22L. The cam is a 238/246 109LSA. Very bumpy and bad mannered cam. The Dyno sheet the PO showed me was 442rwhp @ 5600 and 478tq at 4300 rpm. It is a manual trans, rebuilt as was the rear end.

I'm kind of new to the 'highly' modified scene, but from my brief experience, 500rwhp N/A is a big number to chase apparently.

 

I'm sure you and I can agree that approaching and attaining are 2 different things........

 

Word

I’d plan to go by power curve, more than hp per se.

the problem with the stock ls1, is the power curve falls off the cliff after 4000 rpm. My plan would be just enough gain to carry the power through 5000 rpm, which is really the point of ridiculously high speed on the streets. drag, different needs, but street I’m looking for a good time, not jail time…

im thinking a 6500 rpm capable cam, while sexy, is losing a lot of street manners for real street conditions.

 

I agree with you. But any C5 approaching 500whp on 346 cubic inches, N/A, has long passed the 'losing a lot of street manners' threshold.......

 

Yup. Some of the rigs mentioned above are pretty stout. LS6-ish level power and some 4.10s are calling my name.

 

Both cams I mention above made power well beyond the stock LS1 drop off at 4k. The 232/236/113 made power up through 6500rpm. High RPMs is the only way to get a NA LS1 or LS6 to make big power.

Street manners with a great tune were good, but required some clutch manipulation with a
light weight flywheel. The 4.10 gear improved street driving DRASTICALLY. The car was in the start of the cam powerband immediately. Which made the car a fanastic street car.

I 100% reccomend a cam at least 232/236/113 and the 4.10s. I'll never own another naturally aspirated MN6 C5 without a 4.10 gear.

 

NOT making big power was my point, sorry I didn’t make that clear.

To be more specific, 6500 rpm even in third gear is nearly 100 mph with a 4.10. That’s far less than prudent on the street.

For a street car…a comparatively mild Z06 level engine backed with low gears will drive well, doesn’t need headers, yet provide plenty of “set you back in your seat” power.

Just providing some choices for the OP.