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Old 06-24-2018, 01:31 AM   #1
Domingo
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Question about lS engine vs gen 1. SBC

I cant make my mind about building my sbc 350 with a good of heads such afr or edelbrock vs doing a ls swap.
SBC are plentiful and i know how to work on them on the other hand I know not much about a ls engine other that they are made by chevrolet
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Old 06-24-2018, 01:59 AM   #2
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Re: Question about lS engine vs gen 1. SBC

its hard to beat a fuel injected LS for dependability,power,mpg....if your on a budget it might be cheaper to build your sb though....ill never go back to a carb engine ...love my LS swap...got 2 more lined up for LS now...ones getting a LS3, the other a 5.3 or 6.0...the cost of a basic LS 5.3 has come down and can be bought for under 1k now...6.0s are still high
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Old 06-24-2018, 08:58 AM   #3
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Re: Question about lS engine vs gen 1. SBC

If your planning on aftermarket heads, what you spring for those would be about what an LS swap would run.

I love my LS swap but...I also love the smell of a SBC running a tad rich and hard on the throttle.

Good luck!
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Old 06-24-2018, 10:24 AM   #4
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Re: Question about lS engine vs gen 1. SBC

I like my truck to be on the nostalgic side....SBC for me all the way. They are like a favorite toy.
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Old 06-24-2018, 05:22 PM   #5
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Re: Question about lS engine vs gen 1. SBC

I love the gen I small blocks,,,,,but after playing with the gen III engines, I will never go back! They are tough as the hinges on He!! Longhorn
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Old 06-24-2018, 07:17 PM   #6
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Re: Question about lS engine vs gen 1. SBC

You could get a GM L31-R 350 crate engine for around $2000. It comes with a hydraulic roller cam, 4 bolt mains, and vortec heads. I wouldn't put my money in a motor with a flat tappet cam. The L31 is the last version of the old 350 and I think it the best most improved version. I like the old school look of the 350 but a low mileage ls would be a good motor also.
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Old 06-26-2018, 11:43 AM   #7
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Re: Question about lS engine vs gen 1. SBC

I love the possibilities of the new LS motors. Especially boosted. I'm excited about messing with electronics. I have designed and built several of my own PFI and spark control systems (from scratch) for engine dyno research, so I'm not afraid of electronics at all.

BUT, I'm going totally old school with my truck. I want to keep this one simple, super simple, so I can explain the basics to my kids. Maybe my next project will use an LS.
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Old 06-26-2018, 12:24 PM   #8
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Re: Question about lS engine vs gen 1. SBC

Quote:
Originally Posted by garyd1961 View Post
You could get a GM L31-R 350 crate engine for around $2000. It comes with a hydraulic roller cam, 4 bolt mains, and vortec heads. I wouldn't put my money in a motor with a flat tappet cam. The L31 is the last version of the old 350 and I think it the best most improved version. I like the old school look of the 350 but a low mileage ls would be a good motor also.
I chose the L31 for all those reasons and more. I'm running mine with a Quadrajet and HEI. With a cam change (HT 383 cam) it's good for around 330 horses and close to 400 lb/ft of torque.
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Old 06-26-2018, 12:29 PM   #9
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Re: Question about lS engine vs gen 1. SBC

Im going to look into l31
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Old 06-26-2018, 05:19 PM   #10
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Re: Question about lS engine vs gen 1. SBC

You'll need a different intake manifold and a mellonized distributor gear.
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Old 06-26-2018, 05:31 PM   #11
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Re: Question about lS engine vs gen 1. SBC

... and electric fuel pump.
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Old 06-26-2018, 05:49 PM   #12
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Re: Question about lS engine vs gen 1. SBC

Paint the LS orange
Stick a Vic JR on it with a 4150 throttle body
Move the coils to a hidden location IE top of the trans tunnel
Only wiring you see at that point is the injectors but that easy to hide

It will give you most of that nastolgic look.


But I am shall we say very biased 😁
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Old 06-26-2018, 06:25 PM   #13
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Re: Question about lS engine vs gen 1. SBC

I'm sorta in the same boat. The motor in my 98 runs pretty good, save for the occasional misfire, most likely poppets showing their age. Upgrade is around $250. I can get an LS dirt cheap, but even the 6.0, which has the higher horsepower, is almost out of a reasonable RPM range. My 'ol Vortec with 256k on it, pulls just fine around 3k, and that's where the LS starts to make its power. I'd like to take a ride in a swapped truck, maybe get an idea of what it's like. Cause the last time I drove an LS was an 02 2500HD, and was not impressed.
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Old 06-27-2018, 08:46 AM   #14
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Re: Question about lS engine vs gen 1. SBC

I've 5.3 LS swapped my 85 Suburban and it's the single best thing i've done to an old truck, by far. It doesn't leak, parts are cheap for the swap and replacement parts if you buy smart and do it right to begin with. The reliability is superior and it runs great in any climate/elevation. If you want to drive your rig, LS it and don't look back. If your thing is old SBC engines, get one and enjoy it. The reason I put an LS in my suburban and will soon in my K5 is because I like to drive these old trucks. The fuel mileage alone makes up for the swap quickly if you drive it enough and the power they make is unbeatable per dollar.
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Old 06-27-2018, 09:25 AM   #15
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Re: Question about lS engine vs gen 1. SBC

I hear fuel mileage is better, but then hear they don’t get much better than any over FI engine. Especially the 6.0s. Buddy has one, says 12-13 if he’s lucky. I got that with my vortec 454. I’m looking at one to put a small turbo on, then it’s a whole new ballgame...
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Old 06-28-2018, 10:56 AM   #16
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Re: Question about lS engine vs gen 1. SBC

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I hear fuel mileage is better, but then hear they donít get much better than any over FI engine. Especially the 6.0s. Buddy has one, says 12-13 if heís lucky. I got that with my vortec 454. Iím looking at one to put a small turbo on, then itís a whole new ballgame...
With my stock '04 5.3 I average 21-22 on the highway going 80 with my Suburban. 17-18 in town tooling around. Has 3.42 gears.
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Old 06-28-2018, 06:37 PM   #17
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Re: Question about lS engine vs gen 1. SBC

In general, the old school SBC will make better power down low. **IN GENERAL** (emphasis added for the LS guys who are going to cry because I said that) The LS does make great power but they need to rev to make the power. Yes, you can spend the $$ on turbo or whatever on the LS, but you can do the same thing to a SB with the same result.

How are you going to use the truck?
What is your budget?
What transmission are you going to run?
Tire size and gear ratio?

I know there is the argument that the LS guys love to use about how dependable - turn the key and it starts and runs always. The SBC in my old Jeep did that for 150K miles. The BBC in my dually has done that for 110K miles so far. Anything is dependable if you make it that way.
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Old 06-30-2018, 03:41 AM   #18
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Re: Question about lS engine vs gen 1. SBC

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Originally Posted by DieselSJ View Post
In general, the old school SBC will make better power down low. **IN GENERAL** (emphasis added for the LS guys who are going to cry because I said that) The LS does make great power but they need to rev to make the power. Yes, you can spend the $$ on turbo or whatever on the LS, but you can do the same thing to a SB with the same result.

How are you going to use the truck?
What is your budget?
What transmission are you going to run?
Tire size and gear ratio?

I know there is the argument that the LS guys love to use about how dependable - turn the key and it starts and runs always. The SBC in my old Jeep did that for 150K miles. The BBC in my dually has done that for 110K miles so far. Anything is dependable if you make it that way.
Hey I like you! It tis true what you say, you can make the old school SBC dependable. Its all the the choice of parts you buy.
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Old 06-30-2018, 09:09 PM   #19
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Re: Question about lS engine vs gen 1. SBC

Been through this and while I would love to do the LS swap the money doesn't ad up. I can get an new, not rebuilt L31 from GM for $2k sometimes just under. Comes with a warranty.

If I go LS to meet that price I have to buy a used engine with 100K +/- and I know nothing about it. By the time I am done it will cost more, it's more work to install. No warranty either.

I have been back and forth but I finally decided to go with the L31 even though I would like the LS.
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Old 07-01-2018, 07:27 AM   #20
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Re: Question about lS engine vs gen 1. SBC

Great! Not a thing wrong with your decision, it’s your truck, make you happy!
Good luck! Thanks for sharing!!
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Old 07-01-2018, 11:41 AM   #21
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Re: Question about lS engine vs gen 1. SBC

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Originally Posted by Kudzupatch View Post
Been through this and while I would love to do the LS swap the money doesn't ad up. I can get an new, not rebuilt L31 from GM for $2k sometimes just under. Comes with a warranty.

If I go LS to meet that price I have to buy a used engine with 100K +/- and I know nothing about it. By the time I am done it will cost more, it's more work to install. No warranty either.

I have been back and forth but I finally decided to go with the L31 even though I would like the LS.
This exactly the thing I have considered. All the Electronic upgrades to make it nice and feasible does not add up to any cost savings.

Now if I can take an LS block and do it old school carbonated without the ECU is something I have considered.
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Old 07-01-2018, 06:39 PM   #22
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Re: Question about lS engine vs gen 1. SBC

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Originally Posted by Kudzupatch View Post
Been through this and while I would love to do the LS swap the money doesn't ad up. I can get an new, not rebuilt L31 from GM for $2k sometimes just under. Comes with a warranty.

If I go LS to meet that price I have to buy a used engine with 100K +/- and I know nothing about it. By the time I am done it will cost more, it's more work to install. No warranty either.

I have been back and forth but I finally decided to go with the L31 even though I would like the LS.
If you go with the GM L31 crate engine a lot of people on here will try to convince you to change the cam. Sure it will run good will a cam upgrade but it's not necessary, you wont believe the low end torque you have with the factory cam.
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Old 07-01-2018, 08:39 PM   #23
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Re: Question about lS engine vs gen 1. SBC

A cammed 5.3 with headers and a truck intake will run right with most "built" 383s at your local cruise night. I know you're shaking your head right now, and that's ok. I would have too a few years ago.

150k miles is nothing. In fact, thats about all I mess with. Getting one externally rust free is more important than mileage.

The LS makes plenty of torque down low and carries it over a much wider rpm range than a classic sbc. But I do agree, the classic SBC does seem to make more torque in the sub 2500rpm range.

When compaing the LS to old school, dont judge by driving a stock pickup truck. These engines respond to mods like crazy. Its also not "all in the heads" either. Rod stroke ratio, 55mm cam core, stable valvetrain components, COP ignition, low drag oil pump, replicated ports, long runnner intake, stable block, low tension rings, windage tray, etc etc. They're literally a race engine found in the junkyard. Thanks GM!
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Old 07-02-2018, 12:28 AM   #24
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Re: Question about lS engine vs gen 1. SBC

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Originally Posted by Heavymetl View Post
A cammed 5.3 with headers and a truck intake will run right with most "built" 383s at your local cruise night. I know you're shaking your head right now, and that's ok. I would have too a few years ago.

150k miles is nothing. In fact, thats about all I mess with. Getting one externally rust free is more important than mileage.

The LS makes plenty of torque down low and carries it over a much wider rpm range than a classic sbc. But I do agree, the classic SBC does seem to make more torque in the sub 2500rpm range.

When compaing the LS to old school, dont judge by driving a stock pickup truck. These engines respond to mods like crazy. Its also not "all in the heads" either. Rod stroke ratio, 55mm cam core, stable valvetrain components, COP ignition, low drag oil pump, replicated ports, long runnner intake, stable block, low tension rings, windage tray, etc etc. They're literally a race engine found in the junkyard. Thanks GM!
Went from a L31/Turbo350 (with a quadrajet and HEI) in my Jimmy to a 4.8L/6L90. Clearly the 4.8L is not considered as a torque monster, but I have to agree that LS motors are best above 2500 rpm. With my L31, 2.52 first gear, 3.07 rear end, and 33's it took off hard and would just about do burnouts without the brake.

Going to the 4.8L that makes 40 more horsepower and 40 less torque, it has 4.03 gears, same rear end and tires. The L31 still pulls harder than this setup, until about 3k.

At 3k, the LS engine really starts pulling and will pull all the way to 6500 whereas the L31 falls on it's face around 5k without upgrades.

I did the swap myself and I think I have about $6500 into it total. That's $2500 for engine/transmission/harness, $800 np205 adapter, $600 for hptuners, $600 for fuel system, $500 for manifolds and exhaust, $200 intake system, maf, and $400 for electrical stuff. I could have bought the L31 for $2k and dropped it in an afternoon for about $200.
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Old 07-02-2018, 10:12 AM   #25
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Re: Question about lS engine vs gen 1. SBC

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Went from a L31/Turbo350 (with a quadrajet and HEI) in my Jimmy to a 4.8L/6L90. Clearly the 4.8L is not considered as a torque monster, but I have to agree that LS motors are best above 2500 rpm. With my L31, 2.52 first gear, 3.07 rear end, and 33's it took off hard and would just about do burnouts without the brake.

Going to the 4.8L that makes 40 more horsepower and 40 less torque, it has 4.03 gears, same rear end and tires. The L31 still pulls harder than this setup, until about 3k.

At 3k, the LS engine really starts pulling and will pull all the way to 6500 whereas the L31 falls on it's face around 5k without upgrades.

I did the swap myself and I think I have about $6500 into it total. That's $2500 for engine/transmission/harness, $800 np205 adapter, $600 for hptuners, $600 for fuel system, $500 for manifolds and exhaust, $200 intake system, maf, and $400 for electrical stuff. I could have bought the L31 for $2k and dropped it in an afternoon for about $200.
The way you went about your swap is one way of doing it. Here's what I did...

$600 for 5.3/4L60E, $200 in trans rebuild parts to convert to 2wd from 4wd, the 5.3 I got came with everything from the donor truck and I used all I could from it, $300 in harness modification and PCM flash from Wait4Me performance, $250 for '87 Suburban fuel tank, pump, vette fuel filter/regulator and fuel line parts/fittings from SUR&R, $250 in new trailblazer manifolds/exhaust pipe/parts, $160 in Dirty Dingo mounts and energy suspension inserts for the stock clamshells, $140 for new radiator and hoses, $50 for transmission cooler line parts, $140 for GM Performance parts oil pan and misc. gaskets. I'm into a LS swap for just over $2k. The truck I got the engine from had 140K on it and it runs out great, pulls hard all day without issue, and the transmission works great too since it's basically rebuilt. I've had this combo for going on 3 years and it's been by FAR the best thing I've ever done to a vehicle as far as modifications go. Deals can be had and this can be done for even cheaper than I did it. In my opinion, I'd never spend over $500 on an LS engine because the 4.8's and 5.3's are plentiful and have more than enough power for me. Miles don't scare me at all with these engines and I could care less about a warranty too. This is just my experience and my opinions.

I will also say that I have an '83 K5 blazer with a 350/700R4 and it's going by the wayside next summer for a 4.8/4L80E. I love the reliability and lack of oil leaks of the LS engines, for those reasons alone it's worth it to me. BUT...by all means to each their own, I respect the heck out of the old small blocks too
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