scotty2000ss

iTrader: (2)

What headers are you running?

sean1997ws6

iTrader: (1)

QTP 1 3/4 LTs with the cats on the Y

Mappinsj

Lol. Should have seen me there. I brought in a car that put down 340.

sean1997ws6

iTrader: (1)

no shame. There was a kid getting a dyno tune done on a newer v6 camaro with what sounded like straight exhaust. Orange car too. I waited outside.

sxc Z28

This is killing you.

I saw an LS2 GTO put down 462/429 yesterday with stock cubes, ported 243s, 224/230 114LSA cam, LTs, under drive pulley, and the stock intake/tb. That car was still climbing at 6500RPM. I just mention this because I believe you have quite a bit on the table still. The s60 is definitely robbing you some so keep that in mind.

IMO if you are going to do ANY internal work to an LS and are going for a number, or performance and a good sound for that matter, you should have a true dual system w/ 1 7/8'' catless headers in the budget from the get-go.

Keep at it and good luck with the rest of the build.

sean1997ws6

iTrader: (1)

I thought so too about the headers until I read this:

https://ls1tech.com/forums/generation-iv-external-engine/1498337-1-3-4-headers-vs-1-7-8-headers-my-experience.html

scotty2000ss

iTrader: (2)

Exactly why I asked. I agree with this. A cam with a generous amount of overlap needs a FREE FLOWING EXHAUST.

Sales2@Texas-speed

iTrader: (5)

I can't speak for the above situation but we gained a few hp with a 1 7/8 even in a completely stock ls1 over a 1 3/4. I personally gained 10hp with a h/c ls1 with a 1 7/8 over the 1 3/4.

True duals are probably worth at least 10 as well. I've seen 40 over a pacesetter y-pipe, with a weld in muffler.

SoFla01SSLookinstok

I have seen/read many different things happen with header swaps. Some good some not so good. I don't think you should worry too much about your headers yet. Will 1-7/8 headers help unlock a few more horses? Probably.. as most would think. Although, like the thread you linked, there have been different outcomes to what most would think. Now comes the question.

Why some do what they should & why some don't. I don't think there's an easy answer. My 383, w/ 1-3/4 headers, carries power very well to 6750. Then starts to nose over.

Keep us posted if you do any changes.

sean1997ws6

iTrader: (1)

Id like to get TSP's opinion since it's one of your engines. I figured the engine would build power past the 6,200 mark. The 244/248 cam looks to say 6800 on the website. Are the PRC stage 1 LS6 heads limited?

sxc Z28

Not being a douche but did you read the entire thread or just the OP? By the end they concluded that guy was working with shorty headers, on a corvette, and completely debunked the theory that 1 3/4'' was better than 1 7/8''. On that particular car the 1 3/4'' were simply the better design than the 1 7/8'' he had. That is an isolated incident and completely different from whats going on here.

Doing 1 7/8'' and TDs you will gain everywhere. As Texas Speed said, they see gains on stock internal cars going to 1 7/8''. So on a stroker h/c/i car the gains will be even larger. Since you're on here basically advertising one of their motor builds ask for a forum discount. I would think they could give you a good price on their entire TD exhaust. Their stage 2.5 head program is much better than the stage 1 IMO but that shouldn't be the big problem here.

I'm not high on speculating numbers so I'll tell you the one thing I know for sure, the heads that will turn when people hear you coming down the road and at the strip that's worth the cost alone.

scotty2000ss

iTrader: (2)

I bet he would gain at least 20 and another 10 on top of that with an adjusted tune.

JakeFusion

iTrader: (7)

Those heads aren't helping you...

If you wanted to chase a number and be well over 500... get the 1-7/8" or even 2" headers, true duals, and the PRC 247 heads. With that cam and 383... you'd see probably 510-520rwhp with that setup. And it'd pull to 7000.

Or, cheaper, and easier, would be to add a 200 shot of nitrous to the car.

I can't imagine that 244/248 cam drives that great either. So I'd look at maybe swapping it out to something in the mid 230s. I doubt you'd lose any power and would pick up torque.

Jtm2085

iTrader: (1)

^ don't the prc247's need a 4.0 bore?

JakeFusion

iTrader: (7)

Probably. The 2.12" intake is a bit large for a 3.9" bore.

So maybe the 227 or 237 would be better. If you sell off your Stage 1 heads and buy the new PRC heads for $2400. It's not a bad price overall. It probably nets 20HP and more RPM assuming the FAST 92 doesn't choke it out. The rest comes from the exhaust setup.

And the S60 doesn't cost as much power as a 9" - it's on part with a 12-bolt. So you don't lose a lot despite it being very beefy. It also runs cooler than any of the other rearends.

sean1997ws6

iTrader: (1)

I did see that he was using shorty headers later on. So that is not a good example. Maybe I'll go with the speed engineering 1 7/8. You can't beat the price and people seem to like them. I'm not chasing a number enough to drop a couple grand for Heads, headers and a true dual setup. It's a 2001 with peeling clearcoat on the nose, I'll check the ego haha

sxc Z28

I didn't think you'd want to go through and redo the setup lol the Speed Engineering 1 7/8'' will do fine. The point a few of us in here are making is everybody wants the most power per $ and they go for the h/c or stroker h/c in this case and don't drop the money for the proper induction and exhaust setups to make it work. I would continue to recommend the TDs because you cant beat the performance or sound.

Also, what valve springs did you go with?

sean1997ws6

iTrader: (1)

Maybe Texas Speed will let me test a set of their 1 7/8 headers with their 383 to get the absolute difference they make over 1 3/4. Can't hurt to ask huh?

64post

iTrader: (5)

383c.i. 1-7/8 long tubes through 3" x piped exhaust to Moroso spiral core muffs with Dart 225's, not $2400 PRC's, 92mm ebay TB ......517rwhp @6300 443ftlbs@ 5000. the Moroso's have been scraped and now I am running Dynomax Bullets dumped. Going for some tune adjustments tomorrow to see if helps.
'

big hammer

Adequate airflow to support the 4" stroke of an LS 383 has always been an issue on those engines win the 3.9" bore.

I'd get the biggest CSA head I could get, MSD intake, 2" headers and 3" x pipe duals. Money no object id use mast ls3 small bores.

A 250cc head that flowed 300 would likely work better on this engine than a 220cc head that flowed 300.