LSX compared to SBC
Thread Starter
Staging Lane
Joined: Dec 2018
Posts: 68
Likes: 2
Yep. Had a friend at 18 years old do a stock rebuild on a '79 olds 403. .o24 over, stock replacement hyper pistons, stock poor flowing heads and what would come out to around 7.9:1 compression, stock intake and a set of headers. He was going to be a hero by adding a Comp "292" cam. All said and done he put the "beast" in front of a th350 with a stock stall converter. The choppy idle sounded nice, but the car wouldn't get out of its own way and could barely muster spinning the rears with a brake stand. Just a dog everywhere. He got a good education from that build and learned that parts need to be matched to work properly, now 20 years later he owns his own performance shop. Humility is what leads to progress in a lot of cases.
The valves would float at 5500 RPM but it sure worked great from 5200 to 5499 RPM LOL
Not sure how many times I mentioned I was planning on changing the cam in the LS, already said I was changing the carb and exhaust..those things will be tailored to work with the intake I got of course
Hopefully the combo I pick will be as good as the combo all the local circle track guys copied from me years ago (and still use on there cars today)
You guys are fun lets fight :-)
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
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From: Central Cal.
TECH Regular
Joined: Dec 2011
Posts: 420
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Your other statements on carbs vs EFI make a few flawed assumptions:
1) The air/fuel mixture in the plenum is homogenous (it is not, as dyno plots with 8 individual a/f sensors show on a regular basis)
2) Carbs match EFI in efficiency, more or less. In real world, I would wager well over half the carbed "muscle cars" out there are giving up a significant amount of power/driveability due to the state of their tune.
3) The playing field is level for EFI vs Carb, in the LS world. In the end you are still constrained to the intake manifolds available, or that you make. The best manifolds tend to be the EFI ones.
Carbs work, if you take the time to tune them. Few really do.
What you see, going back to your original point, do LS engines take mods as well as Gen I's... If you took your motor, took your stock 190/191 cam out, put in a 224 cam, and cleaned up your exhaust, you would gain ~100hp, and could spin up to 7000 and utilize the manifold you have. The power is there, you just need to use the right parts. Go to 4.56 gears to utilize the higher rpm range.
How many stock Gen I's will gain 50-100HP with just a cam and spring change?
If it makes you feel better, plenty of EFI guys mismatch cams and intakes all the time, especially now with slapping turbos on everything. They just have a way to compensate for some of their poor combos by turning up the boost.
TECH Fanatic
Joined: Jul 2007
Posts: 1,802
Likes: 332
From: Wilmington, De
Must be some boring-*** races if they are all copying your set-ups.
yes, you are definitely wasting your time trying to tell me how to build an engine since you have no idea who I am, what I've done or what I know. You're doing nothing but making assumptions and spitting out information I already know and didn't ask for. The fact is I don't particularly like the SBC and never said a bad thing about LS engines. If you actually think the SBC is so terrible that comparing a high performance 350 to a 5.3 bone stock truck motor is not fair then it is you sir that is not very smart because you are clearly not commenting based on your own personal knowledge. You're just defending the LS based on an assumption that I am comparing it to something so inferior that the comparison is unfair.....assuming I have the LS setup is so bad that's the only possible reason I could even suggest any sort of comparison between the two.
So to all the haters spitting out the insults please allow me to respond in kind: your mom
So to all the haters spitting out the insults please allow me to respond in kind: your mom
i didn’t know that telling you that you made a poor choice for an intake, is trying to tell you how to “build” a motor. I’m not making any assumptions either. I know for a mf-ing fact that that intake is killing the useable power range of your engine. I’ve tried a performer, performer rpm, victor junior and a weiand team g intake all on the same engine. The performer rpm worked better from idle to redline and made more power all the way around. The victor junior was a major dog. I tried spacers, air filter assemblies and tapered Venturi hats. I tried a carter 600, 750, quadrajunk, edelbrock, Holley double pumper 650 and 750 and a vacuum secondary 750 and the Holley 750 double pumper was much better all the way around with the vacuum secondary, quadrajunk and the carter 600 being the worst performing although the carter was very responsive and got good gas mileage. These parts were all tried on the same 350 crate motor I had in a Monte Carlo. I learned how to jet carbs and set timing curves at a young age. I also learned how to tune before HP tuners was a thing. I had a haltech real time tuning ecm in the 90’s.
I can assure my level of knowledge and experience with building engines, tuning fuel injection, building transmissions, rear ends and fabrication far exceeds yours. I have probably forgotten more than you know.
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Thread Starter
Staging Lane
Joined: Dec 2018
Posts: 68
Likes: 2
Just ordered an AEM wideband and 650DP, I figure the 650CFM will be too small once I change the cam and springs but there's nothing wrong with having a spare carb sitting around I guess.
Launching!
Joined: Jan 2004
Posts: 199
Likes: 20
Lostoned, you swapped in a factory engine with about the smallest factory cam there is.
Built and raced sbc for years. Have 10 sbc in the shop with go fast parts stacked up to build them. Im still going to an LS. If youre just driving around town and spin the tires every once in a while, keep the sbc, you'll be money ahead.
The difference is if you want to make power, a lot if it and actually drive it. LS Heads are so far past sbc stuff, stock castings flow what sbc race heads do. Ive owned and driven multiple 400-500 hp sbc's, complete pain in the ***, but went fast. I can make 500 hp fairly easily with an LS with a decent idle. 600 hp and up LS takes some work but completely manageable and streetable.
Built and raced sbc for years. Have 10 sbc in the shop with go fast parts stacked up to build them. Im still going to an LS. If youre just driving around town and spin the tires every once in a while, keep the sbc, you'll be money ahead.
The difference is if you want to make power, a lot if it and actually drive it. LS Heads are so far past sbc stuff, stock castings flow what sbc race heads do. Ive owned and driven multiple 400-500 hp sbc's, complete pain in the ***, but went fast. I can make 500 hp fairly easily with an LS with a decent idle. 600 hp and up LS takes some work but completely manageable and streetable.
Thread Starter
Staging Lane
Joined: Dec 2018
Posts: 68
Likes: 2
Lostoned, you swapped in a factory engine with about the smallest factory cam there is.
Built and raced sbc for years. Have 10 sbc in the shop with go fast parts stacked up to build them. Im still going to an LS. If youre just driving around town and spin the tires every once in a while, keep the sbc, you'll be money ahead.
The difference is if you want to make power, a lot if it and actually drive it. LS Heads are so far past sbc stuff, stock castings flow what sbc race heads do. Ive owned and driven multiple 400-500 hp sbc's, complete pain in the ***, but went fast. I can make 500 hp fairly easily with an LS with a decent idle. 600 hp and up LS takes some work but completely manageable and streetable.
Built and raced sbc for years. Have 10 sbc in the shop with go fast parts stacked up to build them. Im still going to an LS. If youre just driving around town and spin the tires every once in a while, keep the sbc, you'll be money ahead.
The difference is if you want to make power, a lot if it and actually drive it. LS Heads are so far past sbc stuff, stock castings flow what sbc race heads do. Ive owned and driven multiple 400-500 hp sbc's, complete pain in the ***, but went fast. I can make 500 hp fairly easily with an LS with a decent idle. 600 hp and up LS takes some work but completely manageable and streetable.
Anyway the S10 is sort of my test mule, I planned to go straight to a turbo but figured I might as well play around with NA before I start spending a ton of money on setting up a turbo system
Launching!
Joined: Jan 2004
Posts: 199
Likes: 20
Cam it. I have about that same cam in my daily 4x4 silverado, tows great but its a dog.
Factory performance cams are a cheap swap and easy to find tunes for. Heres some specs for 3 bolt factory cams.
LQ9 Cam Specs. 12561721
Duration @ .050 in. (int./exh.)196/201
Valve Lift (int./exh.)0.467 in./0.479 in.
Lobe Separation Angle116°
3 bolt
LQ4 2001-7
Dur @.050 196/207
Lift .467/ .479
LSA 116
3 bolt
LQ4 1999-2000
Dur @.050 191/190
Lift .457/ .466
LSA 114
3 bolt
LS9
Dur @.050 211/230
Lift .562/.562
LSA 122.5
3 bolt
LS2
204/213
.520/.521
116
LM7 flex fuel
Dur @.050 191/190
Lift .457/.457
LSA 115.5
3 bolt
LS1 98-2000. pt#12560965
dur @ .050 209/198
Lift .500/.500
lsa 119.5 117/122
3 bolt
LS1 01-02. pt#12561721
Dur @ .050 207/196
Lift .479/.467
lsa 116 117/115
3 bolt
LS6 2002-2003
Dur @ .050 204/218
Lift .555/.551
LSA 117.5
3 Bolt
Hot Cam
Dur @ .050 219/228
Lift .525/.525
LSA 112
3 BOLT
Factory performance cams are a cheap swap and easy to find tunes for. Heres some specs for 3 bolt factory cams.
LQ9 Cam Specs. 12561721
Duration @ .050 in. (int./exh.)196/201
Valve Lift (int./exh.)0.467 in./0.479 in.
Lobe Separation Angle116°
3 bolt
LQ4 2001-7
Dur @.050 196/207
Lift .467/ .479
LSA 116
3 bolt
LQ4 1999-2000
Dur @.050 191/190
Lift .457/ .466
LSA 114
3 bolt
LS9
Dur @.050 211/230
Lift .562/.562
LSA 122.5
3 bolt
LS2
204/213
.520/.521
116
LM7 flex fuel
Dur @.050 191/190
Lift .457/.457
LSA 115.5
3 bolt
LS1 98-2000. pt#12560965
dur @ .050 209/198
Lift .500/.500
lsa 119.5 117/122
3 bolt
LS1 01-02. pt#12561721
Dur @ .050 207/196
Lift .479/.467
lsa 116 117/115
3 bolt
LS6 2002-2003
Dur @ .050 204/218
Lift .555/.551
LSA 117.5
3 Bolt
Hot Cam
Dur @ .050 219/228
Lift .525/.525
LSA 112
3 BOLT
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.
The late LQ4 and LQ9 cams are actually the same cam. Some places show a 201 exhaust duration, others 207. Either way it's a good cam for trucks in the 5.3, especially compared to the 191/190 cam they came with.
Thread Starter
Staging Lane
Joined: Dec 2018
Posts: 68
Likes: 2
I’d like a cam that has nothing to offer below 4K, picks up like crazy at 4K and screams to 7k
like I was trying to say I give zero ***** about bottom end torque.
If you ever drove a SHO with the Subaru engine then you know exactly the power curve I like as a personal preference.
I want to max the potential of the heads and intake I got. I might be limited to around 6800 or less with the 706 heads ? since I think the valves aren’t big but I’ll research that point. It shifted at 5,800 in the suburban before I pulled it by the way.
then again there is a very good chance I will just order a wet NOS kit and play around with it (on the stock cam).... it’s a free country why not
You have what is considered to be a "small bore" LS engine. They're not the pick of the litter if you're going to do a naturally aspirated build. The turbocharging crowd likes them for the thick wall cylinder liners though.
I would put the turbo cam in it and keep driving around until you can afford to piece together the turbo system. You're just going to end up with a dog if you try to do a high revving 5.3 with a manual trans and 3.73 gears.
Thread Starter
Staging Lane
Joined: Dec 2018
Posts: 68
Likes: 2
Right. You started with a bottom of the ladder LS that only made 285 HP when new. And you lost torque everywhere with your mods. It's going to feel like a barely warmed over 350 SBC. Nothing wrong with your perception about that. LS engines really really really like a good cam.
You have what is considered to be a "small bore" LS engine. They're not the pick of the litter if you're going to do a naturally aspirated build. The turbocharging crowd likes them for the thick wall cylinder liners though.
I would put the turbo cam in it and keep driving around until you can afford to piece together the turbo system. You're just going to end up with a dog if you try to do a high revving 5.3 with a manual trans and 3.73 gears.
You have what is considered to be a "small bore" LS engine. They're not the pick of the litter if you're going to do a naturally aspirated build. The turbocharging crowd likes them for the thick wall cylinder liners though.
I would put the turbo cam in it and keep driving around until you can afford to piece together the turbo system. You're just going to end up with a dog if you try to do a high revving 5.3 with a manual trans and 3.73 gears.
5.3 is a small bore? Compared to what ? A 6.0 that’s 700cc bigger?
turbo charging crowds like the thick cylinder liners? Since when has that ever been a weak point in ANY LS?
until I can afford the turbo? Spending $ and having $ are different things.
5.3 with a manual and 3.73 gears must be a dog?
Last edited by Lostoned; Oct 26, 2019 at 11:22 PM.
I saw your F-bomb.... just chill, bud. You mentioned a turbo is a lot of money. I was being sympathetic and proposing a cost effective pathway. No offense intended.
I've only made 2 short posts and am not one of the people arguing endlessly with you.
Regarding bore size, yes there are some groupings that are commonly accepted based on cylinder head compatibility. It can limit what heads you have access to, and ultimately how well your n/a engine can perform.
4.8 and 5.3 are small bore They can only fit the heads that came with them.
6.0 and 6.2 are medium bore. Must have at least 4.0" bore to fit the 6.2 cylinder heads.
LS7 is large bore. It's the only OE large bore engine at 4.125" and the heads aren't backwards compatible to any other engine.
You're a veteran engine builder, YOU should know that bore size matters.
I've only made 2 short posts and am not one of the people arguing endlessly with you.
Regarding bore size, yes there are some groupings that are commonly accepted based on cylinder head compatibility. It can limit what heads you have access to, and ultimately how well your n/a engine can perform.
4.8 and 5.3 are small bore They can only fit the heads that came with them.
6.0 and 6.2 are medium bore. Must have at least 4.0" bore to fit the 6.2 cylinder heads.
LS7 is large bore. It's the only OE large bore engine at 4.125" and the heads aren't backwards compatible to any other engine.
You're a veteran engine builder, YOU should know that bore size matters.