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

[Hubscrub]

The only newer motor i've seen i like is 68 stepbed's. I'm not a fan of the new stuff i don't care if it make more power or mileage. Everybody is different i like Inline 6's over a V8 i like 305 is that a reason to dog on these motors no. Drive what you want i do, i drive a fuel injection almost daily but i don't want it in my weekend rides if you tune it right they run just as good and look sweet. and my laptop stays on my desk

[CC69Rat]

Originally Posted by Jon01

Mature.

Relax Bro. All I meant was read the rules on posting For Sale items. You have to be a member to post for sale.

I asked for knowledge on the LS motors, and understanding 'why' That's all .. But Matt's post said it best. Why are these magic LS motors making so much power? That's all I'm looking for. If I had the $4k was it (?) to lay down for an LS, .. absolutely. I'd be all in. But, to just sh1t can my 3970010 matching numbers 350 and drop in the LS so I can drive the same speed and get the same fuel mileage. For ME, and MY usage, it just doesn't make sense with what I know about them. WHEN I start running cones and playing with my GMC, maybe.. but I'm not going to starve to make it happen. I am adopting (more than likely) from Brazil in the next few months, so I'm sticking with what makes sense right now. Just learning..

[Jon01]

LS motors make killer power because they have EXCELLENT cylinder heads and full spark control creating a very efficient engine.

Here's a good read:
http://houstonperformancetrucks.com/...h-flow-numbers

Look at the runner volumes on them as well as the flow rates.
They have huge intake runners and flow incredibly well. Stock, unported 799 and 243 heads flow nearly as much as Dart Iron Eagle 200 Gen 1 heads on the intake side and outflow them on the exhaust.
This coupled with modern cam designs really let them breathe.

You can do the swap for well under 2k if you can chop the harness up yourself and have a local shop to shut the VATS off in the PCM.
There's a place up here that sells complete takeouts with full harness and PCM for $500, I can give you their # if you'd like. Nice guys and always have a couple kicking around.

I'm yanking the 350 but in the end it probably won't be sold, I'm a firm believer in keeping original stuff with the vehicle should someone ever want to return it to OEM. All my stuff that's modded has the original block shoved in the corner just in case. Mostly said that to be sarcastic. I'd probably have a hard time letting it go w/o feeling bad about separating it from the truck.

[19seventeeCustom]

I pulled a perfect running 350/700r combo out in favor of an ls1,
couldn't be happier I did. I wanted leak free, reliable, and more hp than what
my sbc was giving me.....and guess what?...I succeeded.

Throwing money at a 35yr old motor just wasn't appealing to me......but then again,
i'm not old school. pound for pound you CAN NOT beat lsx power and tune ability.

Bottom line though, new tech is here to stay and the bar is only being raised with gen5
bring it on.........

[Danny Bost]

I love my 71 350/350 combo. That being said though, I drive a 2007 3500 6.0 with a fully loaded utility bed on a daily basis. I weigh in just shy of 10K without pulling anything and I still average about 11 MPG. When I drop the hammer on it on the highway I am not at all disappointed. Yes, it does run in the higher RPM range, but that does not bother me. I would put one of these in my truck in a heart beat if I could afford it. I love the dependability and overall performance. Just my opinion.

[69GWC]

Yep I had a 02 2500HD 4x4 ex cab with a 6.0l and 4.10 gears, got 11/12mpg like clock work ran good on the hwy but IMO lacked low end pulling power and I mean for getting the load going from a stop as once it was going it did fine. I think if the tranny was geared lower the truck would have pulled better but first and second gear are geared so high its hard to get the power to the ground when pulling anything.

Most people dont believe me but I did show a few friends of mine how that truck would run 95mph before it would shift out of 2nd gear and I think it was like 50mph before it would shift into 2nd gear out of first, I mean how is something like that going to pull anything very well.
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[el_diablo]

Originally Posted by 69GWC

Yep I had a 02 2500HD 4x4 ex cab with a 6.0l and 4.10 gears, got 11/12mpg like clock work ran good on the hwy but IMO lacked low end pulling power and I mean for getting the load going from a stop as once it was going it did fine. I think if the tranny was geared lower the truck would have pulled better but first and second gear are geared so high its hard to get the power to the ground when pulling anything.

Most people dont believe me but I did show a few friends of mine how that truck would run 95mph before it would shift out of 2nd gear and I think it was like 50mph before it would shift into 2nd gear out of first, I mean how is something like that going to pull anything very well.
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What tires did you have on that thing that it would shift at 50 & 95mph with 4.10s and an auto transmission?

[69GWC]

Originally Posted by el_diablo

What tires did you have on that thing that it would shift at 50 & 95mph with 4.10s and an auto transmission?

At that time it had 305s (33s) on it, but the shift points where not that much different on the stock tires just did not remember the numbers for sure.
If that thing had a low geared tranny I bet it would have been a hoss.
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[CC69Rat]

LS for me as soon as I can, but not anytime soon. Makes sense, all things considered. Thanks.

[Wasted Income]

I'm fully converted to LS. The amount of f*cks I give about Gen I or II SBC stuff is less than zero.

My only regret is not doing it years ago.


Wait.....I mean....they suck...you guys who haven't converted want nothing to do with them. They are junk.


(Maybe that will keep the junkyard prices from rising AS fast as they have been....)

[Heavymetl]

Originally Posted by Wasted Income

I'm fully converted to LS. The amount of f*cks I give about Gen I or II SBC stuff is less than zero.

My only regret is not doing it years ago.

Same here. Its one thing to read on internet boards about the LS, but once you spend some time behind the wheel of a LS powered hot rod (not a stock 5.3 truck), you'll NEVER go back to old school. The ease at which these engines make big power is astounding. Its like magic...but its real.

[68Stepbed]

[BIGBLU 72]

What I plan on doing is a 5.3/t56 and I KNOW a old style SBC won't touch my gas mileage. I know I'm not going to have the grunt of my 406 but when a 5500+lb stock Silverado SS smokes my 68 w a 406 everytime it's hard to Make an argument. The 406 gets 8mpg the SS gets 17 highway and it's AWD. Def not pullin the 406 to swap a 5.3 but a second 67/72 is in the future. My uncle put it best "I love my 350 in my 72 (Vette) but its a lot more fun roasting the tires then gettin 30 mpg in my 04 (Vette)"
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[BrutonLS1]

Still running hoses and finishing up wiring, but here she is.

[Vintage Windmills]

Keep in mind the LS series is not without problems. I've experienced it firsthand in 2 of my trucks as follows:

Stay away from the 99's unless your running an aftermarket intake. These early manifolds could warp and loose their seal. I had it happen on my 99 truck and its been documented online. Dorman later revised the design so it did not warp.

Also my 6.0 lq4 leaks some oil with only 88,000 miles. Thinking Its a good reason though to pull it and do cam/tune/headers and get 450 ft lbs. I do like this engine overall.

I'd like to hear more comments on 96-98 vortec 350's vs. LS 5.3 liters. I've had both in stock form and I'd say (in stock form) the LS1 has little if anything over the vortech. Making mor horsepower per dollar I see the LS1 taking the lead though.

[68Stepbed]

Originally Posted by Vintage Windmills

I'd like to hear more comments on 96-98 vortec 350's vs. LS 5.3 liters. I've had both in stock form and I'd say (in stock form) the LS1 has little if anything over the vortech. Making mor horsepower per dollar I see the LS1 taking the lead though.

Do some reading on LS1truck.com Lots of swaps and other info there about that.

[Ackattack]

Originally Posted by Vintage Windmills

I'd like to hear more comments on 96-98 vortec 350's vs. LS 5.3 liters. I've had both in stock form and I'd say (in stock form) the LS1 has little if anything over the vortech. Making mor horsepower per dollar I see the LS1 taking the lead though.

I've only had one vortec 350 (~110k when I sold it), but I had more issues with it than all of the LS engines I've had (8 or so of them including my suburban with 157k and still kickin strong).

Stock power wise and fuel efficiency not much difference for everyday driving/towing.

[Hubscrub]

I've got a 305 vortec with 200,000 + been a very good engine not problems ever it's a 97 (I know not a 5.7) it will pull haul without issue
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[BHyatt]

I attended a swap meet this Sunday in Indianapolis and could not help but notice the extreme increase in Intake Manifolds and Carb's for sale. I think that the tide is turning away as technology becomes easier for everyone to adapt.

[killer71]

I'm partial to the LS1!
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[Daaaanz67]

Love mine also
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[ol_skool_chevy]

When you guys say " 5.3 are plentiful and super cheap" whats that mean?...i mean one guys cheap is another guys life saving...how much are 5.3 going for?...

[boraxman]

Originally Posted by ol_skool_chevy

much are 5.3 going for?...

800-1200 all day long around these parts/

[ol_skool_chevy]

huh..............this might be something i have to look into more. good info

[H20cooled]

I picked up a 4.8l off CL with 140k on it for $600 with all of the front accessories. I took it apart cleaned everything up and put in a mild cam. The motor looks great very little wear at 140k, it started right up on first try.