Whats your impression of a 5.3L LS motor in these trucks?
 

Hey guys. I was pondering on my new engine/tranny for my truck. This will be my daily driver so I need something will some power but also get decent mileage. My first thought was the 5.3L with 4L60E just because they are plentiful and cheap. But really want a LQ9 6.0L. Just wondering what you guys impressions are with these trucks and the 5.3L, good enough, pleanty of power, mileage? Stuff like that.

BTW this will be going in my 68 SWB C-10. Has a 4.10 gear in it now but I have a set of 3.55s as well.

thanks
CHRIS

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

Subcribed

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

Here she is! I know everyone loves pics! :D

This is the BEFORE pic! Getting ready to re-do brakes/suspension/steering/bushing throughout!
Looking at the "Grand Slam" kit, already have the steering rack conversion so that will be going in as well!


http://i3.photobucket.com/albums/y73...B/DSC06906.jpg

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

I'm curious too. I see the silverados advertised at 12/18 mpg and I have personally owned one (2007 Classic, 5.3 auto with 20's) and it was pretty rough on gas.

How are you guys pulling 'decent' gas mileage out of them? I have a 350 / 3OTT pretty stock with a 1406 Edelbrock, aluminum intake, ramhorns and Flowmaster / 2.25 exhaust and it gets at least 20-22 on the freeway.

My concern is the money it takes to build an older stock 350 or crate motor vs. the LS motor swap and ECM costs of reprogramming, etc. Is it just a cool factor? I'm just not seeing it.

No disrespect, .. please help me understand. If there's something I'm not seeing, please school me. Power is power. It takes gas to make power. 400hp and 25mpg doesn't happen easily regardless. .. LS or an old school v8 ?

Not meaning to open a can here .. just discussion.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

This is a total open discussion for me. Because I have been leaning toward an LQ4 or LQ9 6.0L version. I kinda wrote off the 5.3L pretty early but I wanted to see what other people think that actually have this engine setup and running it. 5.3Ls are plentiful and super cheap. So I am going back and forth... haha

thanks
CHRIS

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

[QUOTE=CC69Rat;5280021] I have a 350 / 3OTT pretty stock with a 1406 Edelbrock, aluminum intake, ramhorns and Flowmaster / 2.25 exhaust and it gets at least 20-22 on the freeway.

I have never owned a 350 that got close to those numbers.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

Here's the facts I've experienced; 1972 Chev 2wd-350cid/350 trans/3:08 gears all stock-17-19 mpg highway, 1995 GMC 4X4-350cid/4l60 trans/3:73 gears-22-23 mpg, 2003 GMC 4X4-5.3l/4l60e/3:73 gears-16-18mpg, current 1998 GMC 4X4-350/4l60e/3:73 gears-20-22 mpg.
My opinion was the 5.3 was guttless in low rpm's and gas mileage wasn't what I expected.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

great question and input...keeping them coming!

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

I have a 5.3L in my 68. Compared to the sbc I've had in these trucks (327, carbed 350, tpi 350, tbi 350) there is no doubt that the 5.3L is way better.

My truck has 4.10 gears and the 4L60E and doing 75 I'm getting about 16.5. However, I had a '05 CCSB Z71 with 3.42 gears (and 32" tires) and I would get 20+ mpg out of that in WA where the speed limit was mostly 60.

Also, with the 5.3L, you can bore it out to a 5.7L and use the stock LS1 pistons in it (same stroke as the LS1).

IMO if you don't have an engine or your old sbc engine needs a rebuild, you'll be happier with the 5.3L.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

I drive like a papaw, 65 on the freeway. I'm pretty easy on it I guess. But I was shocked too. It is the GMC in my build thread. I promise man, I clocked it. Gallons vs. mileage. I drove the truck 312 miles home, the day I bought it. It came out to 24mpg honestly .. but I'm guessing 20 respectively.

I have also had a hot 350 on a 69 Camaro that no, .. it was more like 8-10mpg cause I drove the pee out of it. I have owned a newer Transam with an LS motor, etc. I have seen both sides and I like them both. I'm considering an LS in a C10 one day too. I like them just as much as the next guy and I have watched some crazy power (LS Fest) out of these motors. Much love for them .. really.. I simply don't know as much about them as I do the old Big Blocks.

I also know there's 14,000btu's of power in one gallon of gas. (12,000 BTUs with Ethanol at 10% mix) .. I'm not talking octane ..

So really? Are you guys seeing 25+ mpg out of hopped up LS motors? I'm asking ... Cause if so, I just might go that route if the old 350 ever lets go.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

I got 33mpg out of my 99 corvette with 3.42 gears and a 6 speed. But that weighed <3000lbs, had full exhaust and a tune so it doesn't really compare to trucks, but I was pretty happy with a 400HP ride that ran low 12s and respectable mileage.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

How much would an LS swap cost vs an older 350 MILD rebuild, 600 holley or something built for mileage and a 700r / 200 swap? Im asking, not being facetious.
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Re: Whats your impression of a 5.3L LS motor in these trucks?
 

This is just my opinion, after helping with several LS1 swaps over the years (those tend to cost a bit more than the 4.8/5.3 engines). It all depends on what you have, and what kind of deal you can find.

If you can score a decent 5.3 w/ tranny, wiring harness, PCM etc for less than $3K then I personally think the swap is worth it.

If your are doing this to replace a good running engine, then it's not really cost effective.

You also have to price in whether or not your doing the wire harness yourself or buying a ready made harness. Then programming for your PCM.

If you plan on headers, they seem to get a bit pricey.

My son's truck is low buck for sure. And it will keep the 6 cylinder for now, but I'm keeping my eye open for a deal on a 305/350 TPI setup. I'm rather familiar with them, complete systems can be had for cheap, you can adapt a TBI truck / car wiring harness.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

Subscribed. I've been debating this myself
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Re: Whats your impression of a 5.3L LS motor in these trucks?
 

Keep in mind when looking at mileage that most of the trucks today that the 5.3's push around are much heavier than a 67-67 swb 2x4. You'll see good performance and mileage in the older truck that weighs what, 3500lbs? Compare that to the typical 99 to 07 classic ECSB 5.3 4x4 that is 5000lbs. Phat tony points out that the late 90's vortech's are betterr in efficiency. My experience is that they are very similar to the 5.3. The thing about the LSX's is that you can add a cam and tune and make 400hp pretty easily. They are good motors and seem to last longer before rebuilds. The stock tunes are pretty crappy but a 200 dollar tune goes way further than 200 spent on an older 350. I am building my original 350 with roller cam and Vortech heads to keep my truck numbers matching and I am aware that I am spending more money and getting similar performance to if I just swapped in a stock LSx, however it will be a bit of a sleeper, its a tad more interesting IMO, and there is something appealing about not having all the wiring and computer.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

I wondered how the weight stacked up on the new trucks versus the old. I had a '03 GMC Z71 with the 5.3 and it wasn't horrible on gas.

To me it's all about the initial investment + investment needed to get it up and running.

But I'm cheap.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

Where are you finding these cheap (low priced) LS motors? Everything I find is $3k range and it has a boatload of miles on it. Maybe I'm just not looking in the right place.

I have looked .. I like the LS motors and I have the prime candidate for one if the numbers motor ever gives up. but, I'm not about to change a high nickel 0010 block for an LS unless it makes sense.

At 4.50/gl - 20mpg = ~.22 or .23 per mile. 30mph = .15 per mile.

At .07 difference per mile - For every $1000 additional you spend on the swap, it takes you 14,300 miles to offset the difference. Yes, older gen small blocks can be had pretty cheap and parts are plentiful .. but to find an LS2 / T56 swap out of a GTO for $3k (?) Is that possible? I don't know .. For $3,000 I can build a 350 than will hang with it. Just thinking Apples to Apples. (Cost wise)

In no way stirring the pot one way or the other, cause I like both ! :D I'm just trying to think out loud and help justify the cost, all things considered.

That would be a cool show actually. Take an equally prepared C10 body, and a $5,000 budget. One with LS, one with First Gen stuff. See who wins, kinda like that Supercar show with Tanner Felts. Slalom, braking, 0-100-0, etc. That would be interesting.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

I like the drivability part myself, if it's -20* out or 100*, you just hit the key and it starts. Altitude doesn't affect it, and I've never had anything close to an overheating problem even wirh the A/C on idling.

My truck in my avatar is bone stock,'71 swb 350/350 3:07 gear with a rebuilt quadrajet and my mix of city and hiway driving always gets me 12-13mpg. It will get a swap when I get time!

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

Maybe swap the rear gear and see if that helps (?) If mine becomes a problem i will be swapping too.
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Re: Whats your impression of a 5.3L LS motor in these trucks?
 

5.3 is the way to go......both are stock 5.3s with a 4l60e trans, only thing both have are cold air intakes, and a tune, the blue white one has headers too....plenty of power, and had way better drivability then a 350/350 combo (click on pics to watch video)
http://i25.photobucket.com/albums/c8...h_PA100030.jpg

http://i25.photobucket.com/albums/c8...y/PA310058.jpg

http://i25.photobucket.com/albums/c8...h_100_3365.jpg

http://i25.photobucket.com/albums/c8...h_100_3143.jpg

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

All of the LSX based motors are great.....

Like mentioned if you can find a decent priced 5.3/4l60 I would go that route with very little thought. shoot even a 4.8 would be fun for a daily driver.

You should be able to find a 5.3/tranny and wiring harness/computer for less than 3K

6.0 became more popular/pricey and alot of people use those as replacements for there 5.3 while trying to go faster in there trucks/cars.

In my experience the 4.8,5.3 and 6.0 only differ about 15-20hp each as the cubes increase. Tq is the biggest difference between the 3.

My 03 regular cab 5.3 made 290 to the wheels with exhaust,intake,electric fan and programming. It ran pretty hard for a semi stock truck 14.3 @ 98

If you have a good running SBC I personally think its a waste of $$$ to swap out for a newer motor.If I had to buy a motor I would go with a modern FI set up.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

Nice! what were the dyno results?

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

I hear what you are saying but I am lookin at the super driveability of the new fuel injected engines. I am seriously gonna be driving mine every day rain or shine hot or cold so I want it to be ready and willing. But I also want to have something that has some power and guts to it too! And I think a LSX engine would fit the ticket perfectly.

I will sell my old school 327 SBC and 3 speed on the tree, driveshaft and whatever else I have to move on the boards to hopefully help someone else out with there more stock type build.

lata
CHRIS

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

Cole's on the money. All three of my trucks needed motors and the LSx's are what I chose. Driveability, reliability, FI, mpg's and coolness were big factors. All three of my engine/tranny combos were had for less than $2k...closer to $1.5k on average.

After you do one...the next ones are easier.

I had a 5.3/4l60e in a '04 Avalanche. It pulled a heavily loaded flatbed with a '51 pickup on it...adequately. Not impressively, but it got the job done. I can't wait to see what it does in the '72 2wd I'm building.

... I hope to turn the '72 into a daily driver and sell my 2003 import.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

I have ran across a few of them. I was not ready to buy at the time but I have definitely seen them. Even ran across a LQ4 6.0L / 4L80E with all the wiring harness, pedal assembly and ECM for 1,600! I know multiple friends of mine that have more than one of these LSX engines and they dont have much money tied up in any of them for sure! So it can be done.

I wouldn't even look at any of the all aluminum motors like that are in my Pontiac G8 because they sell for around 5,000. I am looking at Iron Block, aluminum head motors with reasonable mileage on them.

lata
CHRIS

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

Power and milage aren't mutually exclusive.The better the power means a more efficient engine(generally).It's using that power(heavy right foot) that makes the milage drop.The 5.3 may not do any better than the 6.0 as far as milage when driven the sams.The 6 cyl in these trucks seldom gets much if any better milage than the 350 and even some BB.The EFI engines will have better driveability and should do better on the hiway than a carbed engine,but the 6.0 may have better milage heavily loaded or towing than the 5.3.There are just a lot of variables,the biggest being how you drive.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

[QUOTE=CC69Rat;5280451]Where are you finding these cheap (low priced) LS motors? Everything I find is $3k range and it has a boatload of miles on it. Maybe I'm just not looking in the right place.

x2 on that even on the 5.3 around here anyway

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

Can you do mine?
J/K
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Re: Whats your impression of a 5.3L LS motor in these trucks?
 

I totally agree with what you are saying. It is ALL about how you drive! haha

lata
CHRIS

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

I'm still not convinced on the "new" motors either i just don't see it my carb. vehicles as just as driveable as my fuel injection truck to me and i just can't get past the horrible looks of the newer motors vs. the old ones. One big deal for me is all the extra stuff that is with the new ones all the wiring etc. and harder and more $$$$ to fix. just my op.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

subscribed

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

A 327 you say? :) If only I had the money. I use to work at a GM dealership and I loved the 5.3's. I would always make the tires squeal when I took them to get gas.:metal: I wouldn't mind putting one in my '63, it's just the whole computer/wiring thing that would make me hesistant.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

My son has a 2011 Silverado with the 6.2 and six speed auto, it's just an awsesome truck. He gets 20 mpg if he stays at 65 mph. It would be hard to imagine the old style 350's knocking out mileage like that in such a heavy 4x4! Plus it will run the 1/4 in 14.6 !

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

I love the 5.3 in my 2000 Z71 ex cab 4x4. I average 14mpg with it and it will easily hit 18mpg on the highway.

I put a 700r behind a rebuilt 350 in my 67 C10. I average around 12mpg and if I keep my foot out of it, I've hit 16mpg on the highway. By the time I blew money on the rebuilt engine and 700r I could have easily had an lsx/4l60 for probably less than what I spent.

I would love to put a 5.3 in my 67, but I don't want to "spend money again" on the same thing.

Also, don't forget, YES these trucks do weigh A LOT LESS than the new trucks the ls engines are in, however, the 67-72 trucks have aerodynamics like a brick! Believe it or not, GM actually spent a lot of time and money making the GMT800s and 900s as aerodynamic as possible.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

I'm really torn with this type of conversion.Not against it,see the value in it yet not crazy about doing it either. What I like about these trucks is the way they were built. They are modern enough for daily driving even today,only gas costs have gotten crazy. You can fix them yourself with no special tools vs paying $75-100 an hour for a "tech". It's great to have more power than you'll ever need and still get great mileage,but I like knowing I can go anywhere I want in my 40 year old truck and no matter what happens I can fix it enough to get back home. I guess I'd like to have one of each...an old school reliable truck that is a s simple as it gets and a high-tech modern computerized old truck that I hope I never have issues with.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

Yup yup 327 I say. Old school that is. My truck is power nothing and doing this swap would also fix most of those issues as well and add A/C while I am at it.

I was hard headed for a long time just saying I wanted a "simple" carb'd motor and all that and I totally understand that. But I am really leaning towards the newer small blocks because of that great driveability and power potential out of a basically stock engine. My basic plan was (before considering the 5.3L again) was to get a LQ4 or LQ9 6.0L, swap in a cam (for some good sounds and power), add some Camaro LS1 headers (cheap) , add a CAI and go from there. Cant argue with 400+ hp from just a cam swap and tune. I dont have to deal with flat tappets killing my cam because the oils these days dont have the zinc like they need. I mean it goes on and on the reasons for me IMO.

Either way you cannot go wrong. New or old the SBC is the best engine ever made. You cannot argue with torque! Something ford guys would never know about! LOL :D

lata
CHRIS

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

Well said Special-K .. Not suprised brother :D

Maybe I'm just a little afraid of them too cause if it breaks, I just don't know as much about the new ones as I do the old ones. I don't want to get stuck in some sort of Error Code / Fault Code etc. I don't know how to fix. With the old stuff, a Phillips / Flat, and a 9/16 and you can at least get home.

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

I love those lsx based engines. good mileage and great power!!

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

The "Fixability" (is that even a word? LOL) of the newer Fuel Injected and computer controlled engines seem to intimidate a lot of people. With a laptop, the right cable, and the right software package, diagnosing an issue with a newer drivetrain is actually a lot easier a vast majority of the time.

Not to mention the ability to tune the engine with the press of a button or a mouse click.

The newer engines are literally designed to go 100K without any service what so ever, besides normal maintenance. If GM wasn’t confident in these engines, they wouldn’t offer the powertrain warranties they currently offer.

Many of the “problems” encountered with the LSx engines are created by owners who do modifications.

I had a 4th F-Body with a LS1 / T56 combo. That car had close to 100K when I got it. I drove it hard. It was bone stock, no mods. When I got rid of it, the mileage was closing in on 140K. The guy who bought it planned on yanking the motor when it gave up the ghost, and building it up. He’s still driving it. In fact last I heard he was planning on pulling it because the clutch was ready to be replaced. The engine itself was still going strong. He did mention he hoped to see 200K on it before yanking it.

Keep in mind that this car saw the drag strip on average probably once a month. And it wasn’t babied.

I’m currently on the lookout for a 4.8/5.3 combo for the kid’s ’65 C10 we’re starting on. If the price is right, I’ll pull the trigger. In my area it’s actually cheaper in the long run to buy a wrecked or otherwise damaged vehicle and pull the drivetrain and part out the rest. Reason being that people have caught on that these engines are popular for swap material. A guy I used to work with buys the newer style trucks and SUVs with the LSx drivetrain and parts them out. Around here the it’s not unheard of to get an easy $3K for a complete 5.3 with tranny and wiring harness. The other issue is that a lot of potential swappers bought engines, not realizing they needed the wiring harness, PCM and the tranny.

I’ve seen guys try to piece together the drivetrain because they got a “Good Deal” on the engine, only to end up spending as much or more than they would have if they bought the entire drivetrain, ready to go.
As far as cost comparison with building an older style small block Chevrolet, the divide is closing.

Like someone else mentioned, if you’ve got a good running engine now, then swapping in a LSx drivetrain, unless you get a GREAT deal, is not the most sensible choice from an economic perspective.

If you have a truck without an engine, or an engine that needs a total rebuild, the cost could be close to a wash. It all depends on what you want out of the engine in your truck.

Buying a good running very mild 350, cleaning it up and throwing in your truck is a far cry from a properly setup LSx engine.

Building a good performing, reliable old style small block Chevy is not a far reach (in cost) from a stock 5.3. And that’s doing all the wrench work yourself.

That being said, most of us who work on and drive older vehicles, we know that it doesn’t make the best economic sense to begin with. If it was all about saving $$$, we’d all drive a 30mpg + compact car.

Now of course many times we try to use other “arguments” to convince ourselves (or our significant others LOL) that “Swapping in a 5.3 and OD for the 350 / 3 speed will save money.” Sure it will save money on gas, but what about initial investment? The other things needed to do the swap? The wiring work, the tuning etc?

I also see people “justifying” their swap by talking about how much more “driveability” the new engines have.

“Just crank the key and go.”
“No need to adjust the carb etc.”

I don’t know what conditions some of you are driving in, but I’ve had both modern EFI engines, I’ve retrofitted EFI (mainly TPI) engines into project cars, and I’ve also daily driven carb’d engines.

I drove a 408 small block with a single plan intake and a carb setup EVERYDAY, rain or shine. Averaged 20k+ the two years I drove it. Did it get wonderful gas mileage? Of course not, it wasn’t designed or built of that. But with a moderate rear gear ration and a 5 speed tranny, it didn’t do as bad as you might think. I drove that car when the temp was 10 degrees and when it was 100 degrees. I don’t ever remember having to do a lot of “tuning” for weather conditions. It’s not like I was driving in massively different altitudes every week.

In fact I put right at 50K on that engine, and the only thing I remember doing to it was changing the HEI cap and rotor, because I had used a “freebie” replacement when I dropped the engine in, and it crapped out on me.

In the end it will always be the owner’s choice, as it should be.

If you plan on swapping a LSx engine into your truck, and you have a decent running engine now, if your primary reason for swapping is saving money, you’ll likely end up disappointed.

It’s the same boat as people who traded in paid off Surburbans and Tahoes when gas prices first jumped after Katrina. They traded 12-14mpg and no car payment for AT MOST a mpg twice as good, plus the car payment. It would take YEARS for many of these people to ever realize any true savings. But I’m sure they felt better when they weren’t dropping $100 at the gas pump every week.

I guess this long-winded post is simply meant say…

“Do what your wallet and your ability allows. As long as YOU like it, who cares what anyone else thinks.”

Re: Whats your impression of a 5.3L LS motor in these trucks?
 

Great post! I enjoyed reading it! haha Long winded or not! :D

lata
CHRIS