35O vs 5.3??

LVJJJ

Original poster
Member
Dec 29, 2015
65
Blaine WA
When we were looking for a Suburban about a year ago I figured any 350 would have more power than any 5.3. I think 5.3 is about 325 cubes. Logical right? Guess not. We were looking for a low mileage good condition Burb between the years of about 1995 to 2005. I really wanted a 6.0 since we had one in an '05 Roadtrek Class B motor home. Moved the 8,000 lb Chevy Express towing a 5500 travel trailer without breathing hard. However, they don't seem to exist on the used market. We saw some decent newer Burbs but they all had the 5.3 which I probably stupidly rejected them cause the had less cubes. Now I've been reading that the 5.3 is a good tow engine. Is the 5.3 better than a 350?
 

HARDTRAILZ

Moderator
Nov 18, 2011
49,665
That is one loaded question, but a stock GM truck powering 350 is not going to be near the performance of a stock 5.3 truck motor. You would definitely want the 5.3. GM replaced the 350 with it for good reasons.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Yeah, the LS engines are way ahead of the old small blocks, which were developped in the '50's.
 
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Sparky

Member
Dec 4, 2011
12,927
There's a lot more to an engine than just combustion chamber size.
 

Bow_Tied

Member
Dec 21, 2014
453
London, ON
I suggest you ignore the HP numbers all together. Torque is the deal for moving a big ass vehicle like a burb. Look at the torque numbers and the RPM the peak torque is available (lower the better). I think the 5.3 has the edge but you might want to avoid the versions with the cylinder deactivation, I'd rather have the 350 or get the 5.3 tuned to removed the AFM. 350 vortec is older tech but works. What are you towing?
 

littleblazer

Member
Jul 6, 2014
9,265
As an engineer, the LS is way better. But also as an engineer there is a reason why the SBC stayed more or less unchanged since 1955. When you start off with something that is more or less perfect why change it? In reality the ls will be the better bet for almost anything. The LT series at the end of the Gen I/II run were more or less equal to the early LS cars. Both can be made to perform, the LS starts out stock with trick parts for the 350. Having driven utilitys and dumps w that are both ls and small block powered... The tech becomes moot. LS tows a little better but fuel consumption is equal. The LS just pulls longer. In the boating world, 350s were still used after the LS came out. It offered nothing over what the 350 could do there because you are limited to a 5500 rpm cap with most drive lines outside of racing anyway. LS doesn't have the low end torque needed in that area. They can be built to do that but why bother. Any advantage it had was lost. The mercruiser racing engines skipped right over the LS anyway. They knew better and used what they learned from building ZR-1 motors and went QOHC. :crackup:

Just get the LS. It is better. Don't worry about DOD unless there is a problem with it. It does work if the car isn't neglected. Some do have issues.
 
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Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
DOD is a worthless system. Barely saves .5 MPG and uses more oil. Disable it before it dies (if you have it).
 
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DocBrown

Member
Dec 8, 2011
501
The 350s in the '95 and '96 Burbs had boatloads of torque but low HP, 325 lb-ft at 3000 rpm, 200 HP. My '95 Burb struggled to tow a 3500# trailer up hills and in the wind.

I currently have a 5.3 in my Sierra, 338 lb-ft @ 4,400 rpm, 315 hp @ 5,200 rpm. I tow a 4500# travel trailer. It tows the trailer beautifully. I took the trailer to Gatlinburg a couple of years ago and it towed great in the mountains.

So yes, the 5.3 is a far betting towing engine.

The DOD issue was fixed on the 2010s. It's fairly rare but not unheard of. There are a couple of people on here that had to have lifters replaced. Oil consumption is an issue but not just from the DOD. Mine doesn't have DOD issues but does have a fouling #1 plug. Also a known issue. I change the plug once every 6 months. Though not as serious as the DOD issue, if ignored the plug breaks down over time and throws a flashing CEL. I didn't know I had the issue until I got the flashing CEL on a trip and a good guy at a shop in a small town diagnosed it for me. I also go through about a quart of oil every 6 weeks.

My truck has 141k on it right now.
 

LVJJJ

Original poster
Member
Dec 29, 2015
65
Blaine WA
I am towing a 2005, 26' Trail Cruiser which weighs about 5,000 lbs. I have made a number of improvements so that the current engine tows halfway decent. When we bought the clean, pristine, one owner always garaged Burb, it didn't want to go over 65 mph solo and would barely pull our 4500 lb Tahoe at the time. I was really bummed. Discovered it had never had a tune up in the 126,000 miles before we bought it. That helped a little. I've used an MSD timing control for years when we were towing with the '65 Chevy Van, 292, Th350. So I put that on which advances the timing by 15 degrees, it was a noticeable difference, speeds up when advancing it. The found a guy in Missouri who makes custom computer chips (Fastchip) to add more power at WOT, which happens a lot when towing up mountains. Another very noticeable improvement. While at the Palm Springs 1000 Trails I was looking at the very restrictive air box that reduces the air intake to less than 3" and wondered why I hadn't got rid of it yet. Went to a hardware store, got a 2' long 4" diameter dryer duct, took the air box off completely and just ran the duct directly into the air cleaner. Another noticeable improvement, so now it's doing a lot better than it did at the beginning, but still have to drop down to second on 4% grader or steeper, but can stay in 3rd on relatively level, up and down freeways. One day on I-80 we were headed west against stiff headwind, ran in second all day at 45-50 mph, 6 mpg.

Next had my muffler guy remove the cat and very restrictive Y pipe and install dual exhaust (no emission inspection where I live). Even bigger difference, really loud though. My research has shown that the 383, which is a stroker engine with a longer stroke is the engine I need. I've lined up a remanufactured one for about $2000, so as soon as I can find the money, will install that. I'm very familiar with stroker engines as I towed for years with that 65 van that I installed a 292 ci inline 6 which is a stroked 250. The difference between the 2 engines for towing is immense. Huge torque, which what I think I'll get out of the 383, I hope.

Now, what's DOD? What's LS? What's LT? I've lived in the 6 cylinder world for the past few decades so v-8's are new to me. Thanks all.
 

Reprise

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Jul 22, 2015
2,724
Google the following for some interesting reading, if you like knowing about engines (Chevy V8s in particular)

The LT1 was effectively the '2nd generation' SBC. I won't go into the details; you can easily find them online (start with Wikipedia and move on from there)

The LS is the (current) 4th-gen variant of the SBC (although I think the very newest ones are considered a 5th-gen, IIRC). It's the one everyone has been recommending over the old 1st-gen small block 350. You may see them referred to as LSx, where the 'x' will be a number - LS1, LS2, and so on. They vary in displacement, and you can probably find an equivalent to the 383, from a torque (if not a displacement standpoint.) Chevy will even sell you one as a crate engine, but be prepared to open your wallet for one. The LS-series engines are capable of adding 100hp or more fairly easily w/o stressing the motor - these are the motors that go into Vettes and high-end Camaros - some with factory superchargers. Detuned versions go into the pickups / full-size SUVs.

Finally, DOD is 'Displacement On Demand' - GM's name for variable cylinder mgmt on V8 engines (4 cylinders are shut down at cruise). Our TBs and Envoys got them starting in '05. However, the first couple of implementations didn't fare so well once the engine would hit about 80K. I'll let you read the how / why on that, as well. Because of the issues with the earlier ones, some people have disabled that system (more reading!) Supposedly, GM got the bugs worked out about 2010 or so.
 
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LVJJJ

Original poster
Member
Dec 29, 2015
65
Blaine WA
thanks for the explanation. Man, I wished I'd had this conversation before I bought the Burb, cause I really thought the 5.3 wouldn't do the job. Darn!!
 

Shaw520

Member
Sep 20, 2017
289
Northeast
..dont give up on the ole 5.7 yet,... they can be made to runnn!!
 
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LVJJJ

Original poster
Member
Dec 29, 2015
65
Blaine WA
I won't, can't afford not to. Forgot to mention I went 350 also because I try to stay away from too much computer (that's why I really like my 65 Chevy Van, the era of the Univac computer and rotary dial phones). I like to work on my vehicles and when you get into the OBDII, there's probably less you can do to it without hurting something. Can't even disconnect the battery without dire consequences. For a while we had an '04 Envoy 4.2, didn't quite do the job towing and there was nothing I could do to improve performance so it was real boring just driving it.
Just wanted to note that I have proven what I suspected. A 292 6 cylinder has a lot more low end torque than a 350, and except for the lack of enough horsepower at the top, is really a better tow motor. I really miss the old 6, all you had to do to get started was just step normally on the go pedal and it would smoothly, quietly get things started and just keep doing that till you let off the gas. It would also leap across an intersection if I decided to stomp on it. Felt like I was going to rip the frame out from under the trailer. With the Envoy and Burb, they make a lot of racket as they fight to build rpm's just to start moving.
 

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