View Full Version : What's the difference between the LT1 and Vortec 350?

01-24-07, 07:37 PM
I have to wonder, why would GM build two different 350s with approximately the same hp and torque during the same time? It would have saved them money if they just produced one. But then I suppose the Vortec was better for towing and hauling, and the LT1 is better in performance applications like the Vette and F-Bodies. Actually, if you think about it, the Vortec would probably be better suited in the big heavy B and D bodies..

Lord Cadillac
01-24-07, 07:52 PM
You're talking about the 5.7 LT1 and 6.0 Vortec in the Escalade, right?

01-24-07, 09:04 PM
Nope, the 5.7 LT1 in the B/D bodies and the 5.7 Vortec used in the 96+ full sized trucks and SUV's.

01-25-07, 01:06 PM
Nope, the 5.7 LT1 in the B/D bodies and the 5.7 Vortec used in the 96+ full sized trucks and SUV's.

Without having ever done much vortec research, from my limited understanding the Vortec uses a head design based on the success of the LT1. The difference between the two, i believe, is that the LT1 is a reverse flow coolant system, cooling the combustion chambers first before the block (unconventional from the Gen 1 small blocks).
Otherwise the heads are pretty close in design to the cast iron LT1 heads.
I can't recall if the ports on the vortec heads are D-shaped or not like the LT1 heads....

A stranger question, IMO, is why GM produced the L99 engine for ONLY the base model Caprice Classic in 1994 and ending in 1996. The LT1 was optional in Caprices and standard in Caprice & Roadmaster wagons, standard in the Fleetwood, Roadmaster sedan, and Impala SS.
Essentially the L99 was very similar to the LT1 but yet designed for only one car and lasted only three years. Seems like a waste of R&D dollars to me....

01-25-07, 08:20 PM
Yeah it does...maybe they figured all of the fleet taxis wouldn't need a powerhouse like the LT1. I dunno, that L99 is such an odd motor though, as far as power goes.

01-25-07, 08:22 PM
I might be getting a 1999 Suburban soon, so this is interesting to me.

01-25-07, 08:23 PM
'99 Burb? Why? That's an odd car for you Ben, it's not a Cadillac! But it is big, BOV and RWD though..

01-25-07, 09:11 PM
Well, I might be moving back to Detroit soon, so I'll need a winter driver. I've always liked those late '90s 'burbs, and I love big cars. So it fits. I'm looking for one in dark red, like Tony Soprano's, or silver.

01-25-07, 09:24 PM
That makes sense. As far as 'burb's go, I like the 1992-99 style a lot more than the 00-06 style...it's more handsome, simpler.

01-25-07, 10:03 PM
I agree, even though it's square, I don't see it as dated at all. The new ones are a little too cartoon-ish for me.

01-27-07, 11:36 AM
I always related the 92-99 Suburbans, Tahoes and full size Blazers to the 77-92 Broughams, and I always related the 00-06 Suburbans to the 93-96 Broughams because the 92-99 has that classic, square styling a lot like the 77-92 Broughams, yet it doesn't look dated. The '00 Suburban and '93 Broughams are more rounded off, and IMO don't look as good as the ones that came before it. But oddly enough, just like how the 93-96 Broughams feel a lot better on the road than the 77-92's (atleast to me), the 00-06 Suburban drives a lot nicer than the 92-99 model.

02-02-07, 09:47 PM
I had a 96 K1500 350 Vortec Burb and have a 99 K2500 Vortec 454 Burb now.

The 350 isn't a bad engine at all, sorta goofy fuel injection, not like the 454 and LT1 injection. The 454 is flat brute power. But in a drag race, the 350 will keep up, but stick a trailer on, and the 454 just doesn't notice and runs the same. There are a few guys who have adapted the Marine intake to the Vortec 350 which gives you the normal fuel injectors like the 454 and LT1.

The 454 gets 10-13 mpg (a friend of mine claims his 96 454 got 15.5 highway, but mine has never got close to that), closer to 10 in daily driving with short trips, and in this cold weather is getting closer to 9. The 350 rarely ever dropped below 13 mpg no matter how it was driven. And got as high as 17.4 highway.

But note when buying a Suburban. C/K1500 brakes suck. C/K2500 brakes rock. To me buying the 454/4L80E is worth the sucking gas over the 350/4L60E in the massive benefits of the 12" front brakes/13"x3.5" rear brakes with Hydroboost compared to the 11" front/11.5"x2.75" rears with std booster. The difference is amazing.

I like the 92-99 "OBS" or Old Body Style better than the 00-06 "NBS" New Body Style myself. I still might pickup a 00-06 8100 8100 Burb if we ever get the 40+ foot camper that we want. The 454, LS1 style V8 and 8100 both lend themselves to E85 and other mods. The 350 Vortec is very mod limited, you are stuck with the lame pencil injectors that only flow maybe 17 lbs/hr fuel flow. Nothing you can do to fix it short of the Marine intake and std injectors.

02-06-07, 08:19 PM
NODIH, I also like the 92-99 style a lot more than I do the 00-06 style, it just seems more rugged and manly.

02-06-07, 08:41 PM
I do too, the new ones are nice, but a touch smaller than my Burb, and there is just too many buttons and switches. I like the simplistic, all business approach. Mine is an odd one, heater leather seats, 6 way power, heated/dimming outside mirrors, autodim inside mirror, the 454, 3.73's, 4L80E, Hyrdoboost (hydraulic power assisted brakes), RKE, inside rear door lock switch, etc. It has almost every concieveable options available. And I can tow 10,000 lbs. I have seen one guy toss in 4.56's and tow 12000+ lbs. With a Burban!

NODIH, I also like the 92-99 style a lot more than I do the 00-06 style, it just seems more rugged and manly.

I towed 3500-4000 lbs with my 454 and kept forgetting it was even there. Acceleration was almost identical with vs without. Give it a touch more gas, even shift points kept to around 2500 rpm towing. And that is with 3.73's. With the taller tires the truck has, it is the same overall gearing as my Cadillac Fleetwood V4P with 3.42's and 235 70 15's.

02-07-07, 11:30 AM
I'd love to have a 454 if I could find one. I love huge gas guzzling engines. a 350 seems kinda small for a vehicle of that size, even though they still pull. I got to drive a mid-'90s Burbon with the 350. I loved it. It's like a rough riding 4WD Brougham with a bigger ass.

02-07-07, 12:30 PM
A guy on the FullSizeChevy forums just dynoed his L29 454, we are all quite dissappointed in the numbers though.

stock 252.3 rwhp 380.5 rwtq
tune 258.2 rwhp 386 rwtq
tune and intake 260.4 rwhp 389 rwtq

We expected at least 290-300 rwhp tuned. This was a stickshift truck that was tested.


02-08-07, 09:51 PM
Stick 7.4L K2500? Wow, never seen a 5 speed 454!

02-08-07, 09:52 PM
I still gotta wonder why they made the Vortec 5.7 and LT1 at the same time.

02-09-07, 09:44 AM
The LT1 came first, the Vortec was the cost reduced. The LT1 was already emissions certified in the B/D Body, and being the Vortec didn't come out until 1996, the B/D was on its death bed by then, so not worth the $ recertifying emissions all over again. AND who would want to buy a Cadillac with a TRUCK engine? Just sounds like the old 366's that they used to use in the medium duty trucks in the late 60's early 70's that were so loud and weak.

I think it was simply cost.

Yup, the C/K3500's were somewhat common with 5 speeds.

02-10-07, 06:07 PM
Ah, that makes sense. But then why didn't GM put the LT1 in the trucks when they introduced it in '92?

02-11-07, 01:26 PM
From what I can guess, the L03/L05 was fairly new at the time, and they probably had a lot of $$ tied up in tooling (tooling=millions of $$, it is a BIG deal) so they probably had to get a min quantity of parts out of it. Being the L05 and Vortec 350 are probably the same, there isn't much there, but in the heads and intakes, there is.

And the LT1 was not emissions certified in the truck, and likely the short runners weren't quite what the trucks want for low end power. And more importantly it was an expensive engine compared to the L05 and soon to come Vortec 350. But they probably hadn't planned on the Vortec until 1993, at latest, 1994. They have to tool up, and then start to build up, get protos out to validate reliability, power, emissions, etc. So probably the work started in 1992 would be my guess. And being the LT1 had already had some awesome heads, so likley the team that did those heads probably did the Vortec heads, and they had some tall shoes to fill for power.

Again, all a guess, but being I work in Engineering, I see it on a daily basis. I see teams do new programs (what I work) and teams doing refresh programs, and then platform teams doing all new stuff that is for future designs.

I am sure GM works much in the same way....

02-11-07, 07:59 PM
That makes logical sense, and I love logic.