Anyone know why GM did away with the 5.7 as a standard engine in the 25/3500 series trucks? Had one in a '97 and it pulled like a bull dog and still gave good gas mileage.

i dont know but i had one in a suburban and i loved it. i wish my denali xl now had a 5.7 or even better a dmax.

There is zero advantage to the old school SBC.

The new "LS1" based SBC's make more HP, more TQ, use less fuel, make less emissions.
They start at 4.8 then 5.3, 5.7, 6.0 and soon will have a 427ci engine based on the same design. These new engines were actually designed for the 1997 Corvette, and were adapted to the trucks. Symmetrical ports, roller cams, 8 coils, super-fast engine computer, high-flow manifolds, 6-bolt mains, it's a race engine that is detuned.

We had a 2000? Silverado with the 350, and it felt pretty fast back then. It was a good motor, but the new ones are even better.

I agree with McRat.:exactly:

The 6.0 is a very well engineered powerplant. Well beyond the 5.7 in terms of power and torque, and much stronger built engine.

The only thing your "feeling" on a 5.7 that may be better is a much lower torque curve. Get the 6.0 above 3K and your in a good sweet spot all the way to 5500. Get a 5.7 past 4K and your gasping for breath.

If your comparing the 5.7 to the 6.0 than yes, the 365 is stronger...but the 5.7 was replaced by the 5.3, and even though the 5.3 has more HP, the 350 will completely work a 5.3's %ss on any sort of hill or pulling any sort of load. My 1998 1500 SB with a four inch lift, 33's, would leave my brothers (which is now wrecked) 2002 1500 SB in the dust when climing a hill or towing....some of this was due to his was an auto and mine was a manual....but even off the line my 350 could catch up to him once we got around 40mph, and once we were at 85 or so I could start to pull away from him. I really like the new generation LS1 derived motors, I think they are way smooth and powerful...but my 350 got about 1 mpg better than my bro's 5.3. Just saying that the 350 is an awesome motor, i have a 1970 C20 that's gonna have a reeeal hot one built for it one of these days:D

J-HEFF

I love my 5.7

I love my 5.7

Me 2, 3, and 4. (the other is a 5.3...):driver:

If your comparing the 5.7 to the 6.0 than yes, the 365 is stronger Whats a 365? It is a 364cid engine.

but the 5.7 was replaced by the 5.3 Was it??? On 1/2 tons maybe.and even though the 5.3 has more HP, the 350 will completely work a 5.3's %ss on any sort of hill or pulling any sort of load.
All the LS engines in the trucks make their torque peak @ 4000 rpm.
The latest truck rendition of the 350 made it's peak @ 2800 rpm.
That is what you are feeling. Torque coming in at 1200 fewer rpms.
I won't even mention the torque management that is limiting the 5.3 as I don't know the extent of it in a 1/2 ton.

So lets compare the latest available 350 (L31) with the 5.3 & 6.0 (regular, not HO) of today.

350 had 255hp @ 4600 and 330tq @ 2800
5.3L has 295hp @ 5200 and 330tq @ 4000
6.0L has 300hp @ 4400 and 360tq @ 4000

Just saying that the 350 is an awesome motorYes, it was quite an amazing engine with close to a 50 year run of being virtually unchanged! That folks is ENGINEering!

The torque "curves" on the LSx engines (with the exception of the LS6) are virtually flat.

Every dyno test I've seen, the LSx engine mimics the LT1/Vortec engine on the torque and hp up to about 3500rpm, then where the Vortec starts dropping, the LSx keeps climbing. So it "feels" like it has less low RPM grunt because it pulls harder up top.

We've been having this debate since 1998 between the "old school" SBC guys and the LSx guys, and every time we go to settle it on the dyno, the results are the same: Stock for stock, the LSx gives up nothing to the Vortec.

Lawnboy- I apologize for being off by a cubic inch:) ;), my bad. Also, I believe my brothers truck was the 285hp version, did it have as much torque? All I know is that towing the exact same trailer with the exact same weight (two place enclosed snowmobile trailer) my 98 would pull a seven percent grade about 5 mph faster than the 5.3 could. I think this may be because I had a five speed in mine. Just pointing out facts, but yes, the new 5.3 has more HP and TRQ than the previous 5.7 did. And yes, I was referring to the 5.7 being replaced by the 5.3 in the 1500 models.

I'm not trying to knock the new generation gasser motors gm has, they are the best around, and the best in the industry. I really like the new alluminum block 5.3 thats out, isn't it like 310-315 hp from the factory? I think thats pretty sweet.:ro)

I loved my 81 5.7 so much that I turned it into a 383!! OK maybe it was lacking? I have the 5.3 in my 2003 Tahoe!! very impressive off the line! I also have the 6.0 in my 2005 2500 HD not so impressive off the line but out tows the Tahoe! IMHO Scott

I currently own one of each, a '97 K1500 suburban, 5.7, and a 2003 K1500 suburban 5.3. I have towed with my '97. It struggles up grades with a 5000 lb load. I haven't towed with the 2003 yet. Nothing compares to the Dmax though. I have a friend with a 8.1 , and it doesn't pull like the dmax.

I thought GM, when they came out with the "new" V8's made a mistake, as they have a relatively large bore, short stroke. Old school thought was that big bore/small stroke was not good for low rpm torque (hp), as you can see the torque peaks of the new V8's are at 4000 rpm's, as opposed to 2800 for the 5.7, in a better range for towing. Ford's truck's engines, if you have ever checked have a relativeley smaller bore - larger stroke, which I thought would be much better for a utility vehicle. I haven't compared the torque curves of any of the engines to really tell which one was the best. McRat, I take your word on it.

In the recent issue of HR, they take two BBC's, of same displacement, but different bore/stroke ratio's, and compare torque/HP curves. One would think that the smaller bore/longer stroke would make more torque/power in lower rpms, and less in the upper rpms compared to the big bore/small stroke version, utilizing the same cam, heads, carb, headers, etc. There was no significant differnce. Surprised me. If you go to the extremes, there may be a difference.

So, even though the newer V8's have a bigger bore/stroke ratio than the old sbc, they are not really giving up anything, and combined with the new deep skirt block, cross bolt mains, roller lifters, etc. the engine is likely more durable than the old 5.7. However, the new V8's may be more expensive to fix/repair, and more difficult to work on. I haven't had the need to work on my 2003 yet, other than maintenance.

One thing that I think GM didn't do right was the gear spread in the tranny, it's too wide. First is too low, and therefore the gear spread is too wide between the gears. I think if the gear spread was closer, it wouold make a difference pulling up grades, significant grades, as my suburban would poop out at times, because the engine would shift out of the power band.

How long was the 5.7 actually in production?

The 350 started production in 1967.

Last US production vehicle in 2002'ish ??

My theory on the "feeling" difference between the 5.7 and 6.0 is mainly due to the tranny. Didn't most trucks with the 5.7 come with the 4l60e? If this is true, the 4l60 tranny has a much lower 1st gear than the 4l80 and thus would feel like it has more take off power when it is really just a gearing issue.

Does anyone think it's a better thing to have the engine make all its power down low and when it has to shift down it falls on its face than to have an engine make power from mid to top end and take advantage of your transmission gearing and the "downshift"?

My $0.02 on the whole thing.

Didn't most trucks with the 5.7 come with the 4l60e?
I think the transmission offered has more to do with the truck rather then the engine itself. I've seen pleanty of 5.7's with TH350, TH400, and 4L60, 4L80's. I sure wish that the 1st gear in the 4L80's was closer to 3:1 like the 4L60's. Would really help get things moving quicker.


Does anyone think it's a better thing to have the engine make all its power down low and when it has to shift down it falls on its face than to have an engine make power from mid to top end and take advantage of your transmission gearing and the "downshift"?

My $0.02 on the whole thing.

Could you rephrase this last part? Doesn't make much sense to me.

To be honest, I don't know if I can effectively get out what I'm thinking. Lets say for arguments sake, the 5.7 makes power from 1500-2500 rpm and the 6.0 makes power from 2000-4000rpm. Typical highway cruising rpm is probably around 1800-2000 rpm in OD which is right in the middle of the 5.7 powerband. When you come to a hill and the tranny downshifts, the rpms come up to 2500-3000rpm which is past the 5.7s powerband. The 6.0, however, cruises at the start of its powerband and when it has to downshift, you will still be in the powerband.

I'm still not sure if this thinking is correct or has any validity, it just seems like the 6.0 makes better use of the gearing and typical rpms that are seen when driving. I'm also not saying that the 5.7 is a bad motor either, I just think that the LS series of motors are a better design....except the knocking piston thing:)

Had a 91 ext cab long box with a 5.7 ran like a raped ape, all they way up to 235,000 miles with just maintenence (and I treated her like hell) Would still be running strong except the wife totalled it.

I don't have the info on the new engines, but if they found a way to improve on the 'ol 5.7 all I have to say is.....sweet!

Main reason for the change can be summed up in one word..... emissions. Next reason... fuel mileage regulations

The original small block has paid for itself many times over during it's 50 year production run, and it's still a big money maker for GM. It was just time for a change to keep up with EPA regs. The 8.1 isn't as drastic a change from the mark series big blocks, even looks the same externally.

This is just MHO as why else would GM invest millions into basically the same type engine?(V-8,cast iron block,OHV, 2 valves per cylinder, and of course the same 4.4 inch bore spacing)

I have owned several 5.7's and 1 6.0. My last 2 gassers were a '97 ext cab Z-71 and a '99 2500 with a 6.0. Hands down, the '97 was the better truck/motor. I regretted trading it the first time I hooked a load to the 6.0. The 5.7 would get 18-19 mpg on the hwy empty @ 70-75 mph, the 6.0 could only muster 15-15.5. Pulling my horse trailer, both the 5.7 and the 6.0 would only get 10.5-11 mpg. The 6.0 could pull hill marginally better than the 5.7. Pulling my 25.5 ft 5'er, the 6.0 got a whopping 7.5 mpg. (the 5.7 woiuld get about 9-10 mpg) Very dissappointed in the 6.0, I traded it for a D-Max and have never looked back. All that being said, I feel that the 5.7 is a better powerplant than the 6.0. Just my $.02

Although I only owned one vehicle with a 5.7 ( a 3/4 ton pu), I believe it was the best gas motor ever built in the U.S. It had great power (for its displ.) , good fuel economy , and easy to work on. The wide variety of vehicles it went in show its versatility.
I hated to see it go.

My last 5.7 had 510,000 miles and hardly a problem. Heck,the horseshoe bracket warped around 400k, destroyed 8 of 9 "built" 700's, 3 out of 4 rears and not a hint of a problem out of the motor. I changed the oil (Mobile 1) every 12 to 20k and the filter ever 5k. The stupid thing didn't leak or burn oil, donno why? Heck, never even replaced one seal on the motor. I think the 5.7 was a GREAT design! :ro)
-------- I've had the 5.3, the 6.0 and currently have the 8.1. They are all good motors, yet very hungry when power is needed. I think that the 5.7 was such a good motor because most folks only used their trucks for light duty or no duty stuff. TQ curve & RPM along with gearing & typical driving yeilded good MPG's for most. Pulling a heavy load could be done and the fuel mileage dropped but not like it does with these screamers we have today. Pull 1,000 miles with the old 5.7 and then the 6.0. The 5.7 will be a little slower and run a little hotter but it will save about 20% on fuel + it's easy and cheap to fix if it breaks.

originally Posted by J-HEFF
If your comparing the 5.7 to the 6.0 than yes, the 365 is stronger
Whats a 365? It is a 364cid engine.

some of the 6.0 engines are rated at 365hp i believe...