5.7 vortec or 5.3LS?

[0xDEADBEEF]

What are y'all running with those old dinosaur motors? My butt accelerometer tells me my H/C 5.3 swapped RCSB is in the 14.5-15.0 range. I think 13.9-ish with tires and traction if the 10 bolt doesn't grenade.

 

[L31MaxExpress]

What are y'all running with those old dinosaur motors? My butt accelerometer tells me my H/C 5.3 swapped RCSB is in the 14.5-15.0 range. I think 13.9-ish with tires and traction if the 10 bolt doesn't grenade.

If you believe a GPS app, 14.50s @ 94 mph. Have not been down the track but it runs as strong as my stock 2wd Titan did and it ran a best of 14.6 @ 95.

 

[0xDEADBEEF]

If you believe a GPS app, 14.50s @ 94 mph. Have not been down the track but it runs as strong as my stock 2wd Titan did and it ran a best of 14.6 @ 95.

That's pretty quick for a big ol' van.

 

[L31MaxExpress]

That's pretty quick for a big ol' van.

The 383 in it makes close to if not over 500 ft/lbs @ 3,200 rpm and carries the torque curve very well. The converter stalls ~2,800 which helps get it off the line pretty strongly too. From a stop its on the converter until 30 mph then the rpm starts to climb above 2,800 rpm. Once its rolling 30+ mph though is where it really comes on strong.

I datalogged a 2 lane country road 65 to 90 mph passing at WOT, it took about 5 seconds including the time for the downshift from 4th to 2nd. It hit 2nd at around 4,200 and shifted at 5,500 @ 90. I have played a bit with the WOT shift points. For some reason it really likes 5,500 upshifts even though it made peak power at 5,600. It will rev cleanly to 6,200 where it is only down ~20 hp from peak but just seems like it enjoys being down in the meat of the torque curve better than strung out at peak HP. I am actually on the hunt for a reasonably priced 03+ van factory disc brake, 4.10 and G80 rear end for mine. It is a near direct bolt in and with the torque I have 4.10s should be near perfect especially if I drop back to a 30.5" tall tire from my current 31.7" tall tires.

I also noticed the same thing with my buddies 6.0L swapped 97 1500. It carries power well to 6,800 rpm but with a converter stalling 4,000 rpm it ran quicker times at the track shifting at 6,200. I really need to play with WOT lockup on mine and see if I can lock the converter in 2nd and get more pull out of it at high rpm. I guess torque really does win races, lol.

My buddies truck is about to be a whole different animal with a big ol Whipple on it. The throttle body is IIRC a 112mm on it and his power goal is 800 wheel. I want to say he has over 10K in the Whipple, fuel system upgrades, new accessory setup so that the whipple is on its own belt and the built 4L80E and custom converter. I could see his truck touching 10s if not 9s.

 

[stutaeng]

I take mpg claims from folks from the internet with a grain of salt.

You can't compare a souped up very light 1500 chasis vehicle with a modified tune (still meet emissions?) to a heavy 2500/2500HD/3500 with a stock tune. It's an apples to oranges comparison.

My stock K3500 CCLB srw with the 5.7 Vortec I estimate gets 10-12. Same as any gas GM (or Ford or Dodge) 3/4 or 1 ton out there of unless it's a diesel. Will a special tune do better? Probably, yes. I'm not a tuner though and probably 99% of the owners out there aren't either.

I don't hate on the SBC; It was a good engine, but there's a reason why GM decided to kill it 20 years+ ago or whatever it was. If you read the articles from the 90s, GM was getting murdered for having such an old technology engine out there; Ford and Dodge had moved on to newer engine designs by then too. They needed something better and they did an excellent job, in opinion. From the information I've gathered, it seems like the LS was actually designed by engineers and hot-rod folks, NOT your typical accountants or bean-counters! And 20 years later, the proof is in the pudding with the LS craze, which I didn't understand myself to be honest. And even the LS is gone by now because time marches on.

Mind you, this is GM after all. Change for them costs millions for engineering, research and development, re-tooling, training, etc. They'll hang on to something until it doesn't work anymore. The LS is just newer version of the SBC.

If all that was needed was changing a camshaft, heads or pop a new tune, and still met current emissions, we'd be buying new GM trucks with the SBC today!

That's just educated opinion and I respect others' opinions. So carry on.

 

[L31MaxExpress]

I take mpg claims from folks from the internet with a grain of salt.

You can't compare a souped up very light 1500 chasis vehicle with a modified tune (still meet emissions?) to a heavy 2500/2500HD/3500 with a stock tune. It's an apples to oranges comparison.

My stock K3500 CCLB srw with the 5.7 Vortec I estimate gets 10-12. Same as any gas GM (or Ford or Dodge) 3/4 or 1 ton out there of unless it's a diesel. Will a special tune do better? Probably, yes. I'm not a tuner though and probably 99% of the owners out there aren't either.

I don't hate on the SBC; It was a good engine, but there's a reason why GM decided to kill it 20 years+ ago or whatever it was. If you read the articles from the 90s, GM was getting murdered for having such an old technology engine out there; Ford and Dodge had moved on to newer engine designs by then too. They needed something better and they did an excellent job, in opinion. From the information I've gathered, it seems like the LS was actually designed by engineers and hot-rod folks, NOT your typical accountants or bean-counters! And 20 years later, the proof is in the pudding with the LS craze, which I didn't understand myself to be honest. And even the LS is gone by now because time marches on.

Mind you, this is GM after all. Change for them costs millions for engineering, research and development, re-tooling, training, etc. They'll hang on to something until it doesn't work anymore. The LS is just newer version of the SBC.

If all that was needed was changing a camshaft, heads or pop a new tune, and still met current emissions, we'd be buying new GM trucks with the SBC today!

That's just educated opinion and I respect others' opinions. So carry on.

Technology has marched on well past GMs current pushrod engines. From a power per cubic inch stand point GM and Dodge NA pushrods V8s get murdered by every DOHC engine in existance. Variable cam timing on both intake and exhaust cams gives an engine a much broader power band and cleaner emissions. GM had a great idea in the early 2000s with a dual cam in block pushrod engine that for some reason was never persuited. That engine was over 400 hp from a 5.0L and it made as much torque as a 6.0L over a broader rpm range. Newer technology has some cool I6 turbo engines on the way.

I get 18 mpg highway with a brick of a body on a heavy chassis on full 8-lug running gear and still have some left with more tuning.

 

[0xDEADBEEF]

I take mpg claims from folks from the internet with a grain of salt.

You can't compare a souped up very light 1500 chasis vehicle with a modified tune (still meet emissions?) to a heavy 2500/2500HD/3500 with a stock tune. It's an apples to oranges comparison.

My stock K3500 CCLB srw with the 5.7 Vortec I estimate gets 10-12. Same as any gas GM (or Ford or Dodge) 3/4 or 1 ton out there of unless it's a diesel. Will a special tune do better? Probably, yes. I'm not a tuner though and probably 99% of the owners out there aren't either.

I don't hate on the SBC; It was a good engine, but there's a reason why GM decided to kill it 20 years+ ago or whatever it was. If you read the articles from the 90s, GM was getting murdered for having such an old technology engine out there; Ford and Dodge had moved on to newer engine designs by then too. They needed something better and they did an excellent job, in opinion. From the information I've gathered, it seems like the LS was actually designed by engineers and hot-rod folks, NOT your typical accountants or bean-counters! And 20 years later, the proof is in the pudding with the LS craze, which I didn't understand myself to be honest. And even the LS is gone by now because time marches on.

Mind you, this is GM after all. Change for them costs millions for engineering, research and development, re-tooling, training, etc. They'll hang on to something until it doesn't work anymore. The LS is just newer version of the SBC.

If all that was needed was changing a camshaft, heads or pop a new tune, and still met current emissions, we'd be buying new GM trucks with the SBC today!

That's just educated opinion and I respect others' opinions. So carry on.

Pick up a copy of All Corvettes Are Red someday. The book goes into pretty good detail on the LS engine. I believe it was GM's first engine designed using things like CFD, modeling, etc.

It's old tech now though.

 

[L31MaxExpress]

Here is what I mean with GMs pushrod engines getting killed on per per cube. This is a direct injected Ecotec 6.2L with a tune to raise the rev/mph limit vs a bone stock direct injected 5.6L Nissan. Both are crank rated at 420 hp. The Nissan with a 7sp automatic gets 1 mpg better without using cylinder deactivation than the GM does with an 8spd and cylinder deactivation.

GM 6.2L

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Nissan 5.6L

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[0xDEADBEEF]

Here is what I mean with GMs pushrod engines getting killed on per per cube. This is a direct injected Ecotec 6.2L with a tune to raise the rev/mph limit vs a bone stock direct injected 5.6L Nissan. Both are crank rated at 420 hp. The Nissan with a 7sp automatic gets 1 mpg better without using cylinder deactivation than the GM does with an 8spd and cylinder deactivation.

GM 6.2L

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Nissan 5.6L

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My 6.2 is rated at 495 crank HP.

 

[stutaeng]

Technology has marched on well past GMs current pushrod engines. From a power per cubic inch stand point GM and Dodge NA pushrods V8s get murdered by every DOHC engine in existance. Variable cam timing on both intake and exhaust cams gives an engine a much broader power band and cleaner emissions. GM had a great idea in the early 2000s with a dual cam in block pushrod engine that for some reason was never persuited. That engine was over 400 hp from a 5.0L and it made as much torque as a 6.0L over a broader rpm range. Newer technology has some cool I6 turbo engines on the way.

I get 18 mpg highway with a brick of a body on a heavy chassis on full 8-lug running gear and still have some left with more tuning.

Agreed on the HP/displacement on DOHC vs pushrod. Great for a light vehicle. Too bad those DOHC engines in those trucks get almost the same mileage a 3/4 ton with a pushrod, but with half the payload capacity.

I think the DOHC engine you speak of was actually the one used in limited numbers in the Corvette in the early 1990s (LT-5?). I've read it was this engine along with Cadillac Northstar DOHC what was used on the LS as "lessons learned," along with everything else. Maybe you are referring to something else?

And apparently the Ford engineering team didn't get the DOHC memo, as they decided to use a pushrod for the Godzilla and those engines are used in F350/450/550/660. So, VERY heavy duty truck workhorses and insane block stresses I would assume. Did they copy the LS? Not even direct injection but MPFI!

To answer your comment about a 1500 with 8 lug axles being a heavy brick: Yes, it's still a 1500 as far as know. Maybe the first generation Express vans were different? The second generation I'm sure are different frames. The 8 lug seem to have a deeper frame and the body sits much higher than the 1500s.

I don't come here hating on someone because they drive this or that or want to LS swap whatever. If I can help, I'll help. I usually hang out on the diagnostic threads as that's what I see folks struggling with the most (which I feared too as a DIY-er.) Or I'm posting about food! LOL. If I don't have anything positive to say, I try to stay out. Sometimes I'm a little too comical. You gotta smile at the world and live a happy life! Life is too damn short to live hating $hit. Don't be a hater. Sorry to say this but that's how I roll.

Today I dropped off some ramps at my little brother's house. He's got a C1500 350 TBI the previous owner dropped in Jegs crate engine right before sold. It's lived 40k as a daily, but has been burning oil for a while and recently losing coolant. He had his 700R4 rebuilt when he just got it and lost OD months ago. He's been driving it like that and now got some misfire he can't figure out. He's throwing the towel. I told him to sell it and get a GMT 800, as that's what I have and very happy with them. He thought about it hard, and he really likes the OBS, so finally decided to park it and do an engine/trans swap. He's not rebuilding the old stuff. No, don't tell him the TBI will run circles around the LS; he ain't buying that story anymore.

I'm just helping with a basic VATS delete, tools and whatnot. If anything, I'm pushing him towards the 4L80e. I don't know anything about TBI-era trucks, so he's actually teaching me. I'm kinda proud of him for taking on this project honestly. Dad's certainly not a gerhead, and neither of us are, but thanks to the internet and an abundant supply of junkyard LS engines, and forums, dropping in a slightly more modern engine into an old truck is doable by the average redneck Bob or Jose without being a true gear head or spending a fortune on fancy internals. I'm not ashamed to say all of my LS engines are stock either and so will this one.

So I may start posting a bunch of questions about TBI-to-LS swaps here in a bit! Don't hate on me.

@0xDEADBEEF Yes, I read the engineers used Finite Element Modeling (FEM) and a bunch of other advanced design stuff for the LS design. For the time being, that was state of the art. You have to remember those software programs were in infancy in the early 1990s; prior to that stuff was calculated with slide rules and then those punch card early computers. I'm glad we don't have to deal with that anymore.