I just bought a LS1 drop out today. It's from a 2002 C5. I'm saving a 1998 roller Z28 and want 380 rwhp. Anything over that is fine. The car was once a T56 and I'll be purchasing one for it. The car will be a cruiser only and will take it to the track maybe 3 or 4 times a year. I realize I'll probably need to switch gear ratios in the rear end with an aftermarket cam.

My plans
Port the stock heads.
Headers, y-pipe, 3 inch exhaust.

Now for the cam.
Lunati black magic stage II. 275/291 while the duration at .050-inch is 225/238. Lift comes in at.612/.585-inch and LSA/ICL is 113/110 degrees.

Is this a good combo?

 

Pretty easy to hit ~380 whp hp cam only these days with LT headers and good tuning.

I wouldn't spend money on porting a set of stock 241 LS1 cylinder heads. If staying GM cylinder heads get a set of LS6/243/799. They will do well stock unported with a spring upgrade. If you really want ported send to Total Engine Airflow, Frankenstein or other reputable head porter. Or consider aftermarket.

Good set of 1 3/4 or 1 7/8 long tube headers, Y pipe with Flowmaster style merge will really help. I'd also add a Fast intake either a 92 or 102 and plus matching Fast intake.

As for the cam, Lunati black magic. The black color is probably from being nitrided. Nitriding has been around for a long time. I'd pass on Lunati and go with Cam Motion.

Lunati black magic stage II.
275/291 while the duration at .050-inch is 225/238. Lift comes in at.612/.585-inch and LSA/ICL is 113/110 degrees.

It's more of an LS3 spec cam accordingto Lunati. Cathedral heads usually don't need a 13 degree split.

Black-magic-stage-2--ls-gen-iii-gen-iv-ls1-ls2 is probably the cam out of their black magic list I'd consider.
IN/EX 227/234; Valve Lift IN/EX:
.614"/.576"; LSA/ICL: 113/111

The extra 2 degrees on intake will help cathedral heads breath and it still has a reasonable split at 7 degrees.

Sounds fun build, best wishes.

 

Thank you for that information! When I got this roller I decided I wouldn't dump a ton of money into the motor/trans. I'm currently finishing up a LS3 swap in my IROC. That car has a wilder type build. I went all in from the intake, TB etc.

I was hoping that porting stock LS1 heads would be cheaper than aftermarket heads? I think it might be hard to sell my current LS1 heads in order to swap for LS6. I really don't know though. I haven't owned any LS motor since 2007!!!

So is porting the stock LS1 heads cheaper than the other options you provided?

Thanks again for your response. Some great info there!

 

Paying to port a stock set of LS1 heads is the worst bang for you buck.

I have a set of fresh Advanced Induction ported high compression LS1 241 heads with 58cc chambers and Tick dual springs, I'll happily sell you if you really want ported LS1 heads.

LS1 heads are probably ~$100 to $125 if you can find a buyer.

So is porting the stock LS1 heads cheaper than the other options you provided?[/QUOTE]

Porting a stock LS1 head will cost basically the same as porting an LS6/243/799 head. A porting a 5.3 head will cost the same but be slightly more expensive if you move up to 2.00+ intake valve.

 

It all comes down to budget but best bang for the buck, I would recommend:

243s definitely over 241s. Will do for 380+ rwhp. No need to port. Would consider milling to clean surface and run Cometic .040 to improve compression and quench.

If Ls6 intake, will do for 380+ rwhp.

Cam will depend on driveability you want... If smooth on a 113-114 LSA. If rougher choppier, then 111-112 LSA. Duration on intake about 226-228 with exhaust of 232-234, so with like 4-8 degree split.

1 7/8 long tubes with flowmaster y merge into a free flowing 3 or 3.5 muffler.

Rear gears I would say 3.73s for strong cruiser.

Good luck with project.

 

You are really splitting hairs when it comes to 243 vs 241. sure the 243 outperforms the 241 a little but it's not like you're losing 50hp. Stock vs Stock the 706 makes the most power.

I would send the 241s in for porting since you already have them. no need in trying to sale those then trying to buy some 799s or 243s not knowing if they are actually any good etc etc. what I'm getting at is that's a lot of headaches for 20hp difference.

i run advanced induction ported 241s on my car and you see my times etc in my sig.

Frankenstein stock casting port jobs are on sale right now. BTW.

You should choose your cam based on your plans with the car. anything in the upper 500s - 600 lift and high 220 duration should easily make your desired hp goal.

that's just my .02 on it

 

Get a set of stock 862 heads off a 5.3 Tahoe and have them ported. They should run well and should only be $200 max for a pair.

 

I run CNC ported 241, I had excellent results, nearly 30 rwhp on my old combo. It surprised the shop themselves and delivered that improvement on the track too.

When changing cams, I asked the porter if I would benefit from tracking down 243s and getting him to port them to replace my ported 241s. He said there was basically nothing between the two finished products and he wouldn't do it himself. So, I didn't bother and he didn't get more work out of me 😉

 

I've had lots of good advice from everyone in this thread. Ive been thinking this is still my best option given Im not looking for anything over 38x hp. Avoiding the need for a different set of heads will save me money. If I wanted 400+ hp I would definitely ditch the 241s.

I'm going to ask around and find a reputable machine shop locally or within a days drive. I can avoid some cost and hassle of shipping heads. Ive been searching, reading reviews etc. I wont drop my heads off at the first speed shop that promises results.
This car is more about saving than creating a HP monster. I don't think anyone would have taken it on for a project. If anything it would have been purchased to part out. The entire interior is toast. I wanna feel like Im driving a new LS1 Z28, like what I once had. My former car dynoed 370 rwhp. Absolutely loved it. All of the interior will be replaced and probably with new or like-new parts


*edit* For me, going too far above the original hp rating starts to feel like a different car. My 2001 started to feel like that and it was only 370hp. When it's crunch time, I may end up keeping the stock heads as is.

 

I understand what you're saying.

I have a 2004 Monaro LS1 manual (basically the same as an 04 GTO) and I run around 380 - 400 rwhp depending on Dyno and our Dyno in Australia read lower than the US. With my Ported 241, I run a TSP 216/220 .600 / .600 112+2 cam. So, nothing impressive, but it's also in tandem with a factory style twin 2.5" exhaust, short headers and cats. The results are actually good with so few mods. My car started with a dyno sheet showing a paltry 230 rwhp!

However, I was chasing low to mid range street performance and got it. The car doesn't feel much different to standard other than being much, much faster. It's a proven mid 12 second car in 100% street trim, road tyres, Coilovers, big brakes, full interior, etc Exactly what I wanted. The only change I'm thinking about is a new manifold.