5.7L engine, why no more?

Chris97K1500 · October 11, 2003

This may have been beaten into the gound, but a thread about the comparison of a 5.7 to a 5.3 just made me think about why GM stopped improving on the 350? Why didn't GM just put in the LS1 with a different cam and get one heck of a 1/2 Ton truck engine? Sort of like the Hemi, only better ! This has always puzzled me. Just thought I'd ask to get any ideas? Thanks, Chris

99-2door · October 11, 2003

Well, I can tell you one thing the LS1 5.7L shares just about the displacement size only with the previous generation 350s. As for why they didn't use the 5.7L in the trucks??? May have something to do with the block being aluminum.

Tungsten · October 11, 2003

Well, I can tell you one thing the LS1 5.7L shares just about the displacement size only with the previous generation 350s. As for why they didn't use the 5.7L in the trucks??? May have something to do with the block being aluminum.

Yes, but they had to make the 4.8/5.3/6.0 non aluminum. So I am sure they could do it in a 5.7 flavor. But then why not give the 6.0 to the halftons?

01Burb · October 12, 2003

Maybe CAFE standards. Keep the overall MPG of thrucks/minivans/SUVs up.

KonradSayek · October 12, 2003

Ive heard that there were NBS Chevys made in and for Mexico that had Vortec 350's in them. They were called 400SS or something like that.

1999GMCZ-71 · October 13, 2003

the 5.3 is a good engine, better in my opinion than the vortec 350. The vortec has one thing on the 5.3 and thats low end torque.

Chris97K1500 · October 13, 2003

I'm not saying keep the 5.7L Vortec. I meant why no 5.7 LS1 engine. Why lower the displacement to 5.3? The 5.7 LS1 with a low end torque cam and a bit lower compression ratio would be a much better option than a 5.3. And I like the idea of why not just offering the 6.0 in the 1/2Ton trucks? I know the 5.7 Vortec that is in my truck may not be better than a 5.3, but it's not like it's night and day with performance between them. If the 5.7 LS1 was in the NBS trucks, then there wouldn't be any comparison of performance, the LS1 truck would win hands down. Sort of like comparing the Hemi to the older 5.9's in the Dodges. If the 5.7 LS1 engine was in a truck, it would probably be around the 330-340hp/365ft/lbs. of torque, based on what they get out of a 6.0L. Sorry, should have made it more clear of what I was comparing. Chris

Mega Dogmeat · October 13, 2003

The 1st and 2nd gen small blocks were all based around a 50 year old design...

GM couldn't carry itself into the new mellenium, while meeting the power and emissions needs of people today...

Ultimatley, the new small block is just another evolution in engine design, just as the old small block was an evolution of the design from the 40's and 30's, etc...

The old small blocks major downfalls were emissions, that was probably the sole biggest reason they needed a new ground-up design.

They were out of room to grow with them, etc...

Chris97K1500 · October 13, 2003

I totally understand the reasoning of the older version 350's replacement with the newer 4.8, 5.3, and 6.0. But why not just put the Corvette 5.7 LS1 in the NBS trucks? Why did they lower the displacement? I think the 5.7 LS1 would be a much better engine for the NBS trucks. There is no major difference in technology between the Corvette 5.7 LS1 and the NBS truck engines. They are based on the LS1. I guess I just hate the fact that GM unless they change things are going to have the lowest hp and torque in half ton trucks (not talking about sport trucks), basically because they are going to have the lowest displacement. Nissan's new 5.6L will have more hp and torque than GM (although, it's an unproven engine). Toyota is working on a bigger V8 engine. Never thought I'd see the day an import would have a bigger, more powerful engine than GM. I really think GM better make a change with it's engines, or they will be playing catch-up, which seems to be there claim to fame. They need to quit putting the same displacement engines, in different vehicles, all with different hp and torque #'s, ie, the 6.0, how many variations are there? Hopefully the people at GM will wake up when imports start to put out more powerful engines in full size 1/2T trucks. To me, the only manufacturer of the big three trying to keep ahead of the curve is Dodge. I got to ride in a Hemi truck this weekend, all I can say is wow, unless you've been in one, you just can't explain how this truck pulls through the rpm range. I've always grown up in a GM only family, but I must admit, I see myself looking at other trucks and really liking what they are doing. There really isn't much difference in reliability like there used to be. All truck manufacturers have their problems. Sorry for the rambling, it just that GM puzzles me sometimes! Chris

GnatGoSplat · October 13, 2003

I agree with 01Burb.

I think it has everything to do with CAFE.

Otherwise, why bother putting 4.8's in trucks when a 4.8 and 5.3 are identical except for the crankshaft and pistons? It's no cheaper to manufacture the 4.8 cranshaft and pistons than the 5.3 versions. In fact, it would have cost less to cast only one size of piston and one crankshaft.

That's also the same reason why there's no 5.7, they guzzle more fuel. Maybe not much more, but when you add in the hundreds-of-thousands of trucks that GM cranks out, that adds up. It actually cost GM more money to have a 5.3 (and 4.8). Even if they would have gone for an iron block 5.7, they could have used the same pistons from the LS1 and saved money there.

I don't think it's GM's fault, I think they would love to use one common engine size as that would save a lot of money. It is all about CAFE and pleasing politicians.

OUMike · October 13, 2003

Ive heard that there were NBS Chevys made in and for Mexico that had Vortec 350's in them.

Yes. These trucks exist, but the motors are NOT revised by any means. The 5.7L in the NBS Silverados and the one in the 98' era ones are the same. Both 255hp. After I found out about this I did some reading up. I've never drivin' a 5.7L equiped truck, but I have drivin' the LM7 equiped ones. I like the LM7, seemed very responsive and was much zippier than my Vortec V6. LM7 had good mid range torque, seems like it'd be a great hauler. My next truck will definatly be an LM7 SWB Silverado...altough a 2-door Tahoe sounds good too.

BTW - The LM7 motor (5.3) and the LS1 Corvette motor have just about nothing in common. Nor do the Vortec 5700 and LT1. That is a common misconception.

I'm not sure why GM just didn't go ahead with the LS1 in the pickup bodies...or something built from it. Might have something do with fuel efficiency when pulling or something along those lines. Might be CAFE problems. I know the 5.3s don't get great fuel economy and I can tell with our 01' Z28 is even worse. I'd kinda like to see a trigger shifting Silverado

99-2door · October 14, 2003

BTW - The LM7 motor (5.3) and the LS1 Corvette motor have just about nothing in common. Nor do the Vortec 5700 and LT1. That is a common misconception.

I'm not sure why GM just didn't go ahead with the LS1 in the pickup bodies...or something built from it. Might have something do with fuel efficiency when pulling or something along those lines. Might be CAFE problems. I know the 5.3s don't get great fuel economy and I can tell with our 01' Z28 is even worse. I'd kinda like to see a trigger shifting Silverado

Actually the 5.7L LS1 and the 5.3 have lots in common, the Gen III engines are all derived from the LS1 and many parts are interchangeable. As for why the 5.7L LS1 is not used in the trucks, I would assume it is because of CAFE standards and the need to keep emissions and fuel consumption under control. CAFE includes domestic cars, import cars and light trucks. There is also a gas-guzzler tax imposed on eash purchaser of a vehicle that does not meet the minimum MPG requirement. It is only Corvette's exceptionally light construction and efficent drivetrain that allows it to get 28 MPG highway keeping it under the limit. The LS1 probably wouldn't do so well in trucks. this accounts for the demise of the ZR-1 (The LT5 was not OBDII compliant) and I think one of the top reasons for the halt of the F-body. This also explains why the 6.0L is not available in 1/2 ton trucks. With the introduction of the Hybrid powertrain in 2004 maybe we can see more powerful engines show up in our vehicles while retaining the CAFE standards. More likely though that CAFE standards will be raised to keep up

Chris97K1500 · October 15, 2003

I guess those reasons are good enough for me to justify a 3/4Ton truck. I like the sportiness of a 1/2Ton, but I want more power than is offered in a GM 1/2Ton. What exactly is CAFE any ways? Some sort of air emission law? Chris

k1500chevy97 · October 15, 2003

Even though they stopped putting it in vehicles the 350 is still the best engine ever made by GM and IMO the best SB engine ever made

GnatGoSplat · October 15, 2003

I guess those reasons are good enough for me to justify a 3/4Ton truck. I like the sportiness of a 1/2Ton, but I want more power than is offered in a GM 1/2Ton. What exactly is CAFE any ways? Some sort of air emission law? Chris

Corporate Average Fuel Economy.

I think the current standard is all light trucks must meet an average of at least 20.7mpg.

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