Well can't deside if I should save up for an LSx engine, go carb, or EFI, but everyone around my area wants an arm and a leg for these ls1/2/3 engines so what about the LQ4 (I beleive) 6.0 vortec engines? Are they pretty close to being the same as the LSx engines? Could try be built to produce the same hp range as a built LSx? Just see if its a good idea or not, I've got a whole year to save up since I'm only tackling the body work this year on my 89 RS

 

http://www.lsxtv.com/tech-stories/en...ags-to-riches/
http://www.superchevy.com/technical/...p/viewall.html

 

Cool, thanks! Great information

 

Although I generally don't like car magazine tech articles,I do want to say thanks for the links.

I have been mulling over what Chevy engineered in the LSx engines.Certainly a smaller c.i. size to get the gas mileage along with the spark/fuel curve.Then the mechanics is a longer rod length/and stroke change to try to get the performance.Also increase in SCR with aluminum heads and a increase in head flow rates with the same.These are common practices used with aftermarket parts with first gen SBC's small bore lacking.

Everywhere I look at the LSx engines the torque curve is much higher in the rpm range vs the first gen 383's.I mean off idle with a first gen 383,@ 2500 rpm I am well into the 400 ft lb range of torque.That would make sense because the physics doesn't change of a smaller c.i. engine always shifts the power curve higher in the rpm range.

It seems to me the the Chevy engineering turned back the hands of time back to the 283-327-350 days with these LSx engines without much opportunity to over bore these engines short of very expensive re-sleeving the blocks and custom pistons.And that even after 14 yrs of production the aftermarket hasn't produced enough sells so the aftermarket block pricing is still very expensive.

I'm posting these comments for the benefit of the O/P and to get some feedback from you guys about my thoughts.

 

Just to finish my train of thought.Short of a wekend racer,just a driver on the street,higher rpm's used for that maybe 1/2 dozen times a yr,seems like a pretty expensive outlay of cash for hp. For the tended street use torque would daily give a better turn of use with a lower rpm torque curve in the 383's.

Again-looking for feedback.

 

Lq4 basically is iron version of the ls1-ls2-ls3 etc. they basically have same heads as an ls2 but with bigger chambers for lower compression. You can swap on ls1-ls2-ls3 heads for a variety of combinations but really unnecessary. Can swap truck intake for car intake and have an ls look alike.

Cam swap tho on stock lq4 will do 11 sec passes no other changes so they make great performance.

Just bolt ons and a tune they can turn 300 whp or more. Thats low 12's in the right chassis

 

But aren't the lq4 blocks come factory with 300 hp?

 

On motor, they are between 300 and 360 i believe depending on model and year. Thats not 300 at the tire.

One truck i seen dyno'd right before i put my 6.2 truck on was 270's whp stock tune with air intake and shorty headers. After tuning made 308! 370 wtq. Very stout lil motor. My 403hp 6.2 factory L9H made 330 after tune. Fbody would have less drivetrain loss

 

Ah gotcha, well I'm planing on going with the t56 and swap in a 4th gen rear end and have 3.73 or 4.10 for gearing, but like I said, I've got a whole year to save and figure out witch way to build

 

smbigfoot89rs.....do yourself a favor and read the sticky at the top of the lsx forum.

then utilize the search function, these two things alone will answer most of your questions.

i spent 4 months doing my own research before i started asking questions. build a budget, add 30% to it, and go from there as far as build costs. the 30% will help cover everything you didn't think of.

 

I had read a few stickies and found them helpful, budget was I'm going to be saving up at least 6 grand this year, since most say 5-8 grand for an LSx swap

 

Thanks Orr.I heard the 6.0's are pigs for gas mileage.Are they??.

 

They have to be. My 5500 lb crew cab with 6.2 and 6 spd auto with variable valve timing drinks only 93 oct and gets 11.5 mpg daily. Its a pig on gas but it sure is quick for a big truck. 403hp rated before tune i picked up 20-30 rwhp with basic tune. Air intake is next, already put muffler on it.

6.0 may be abit better with less power and cubes but still aint great with heavy vehicles.

Now same motor in a 3400 lb fbody you should see mid high teens city, maybe more? Light vettes with ls3's 6.2 run pretty good, mid 20's highway.
Weight makes a big difference

 

I know the 6.0 vortec in my 04 2500 hd that I had got 8 mpg city, but for some odd reason always gotten better gas mileage when I'm pulling something (11/14 mpg)

 

i get 18 in my 2012 F350 around town and 20 highway and 16.9 pulling a 16k trailer (gm screwed up with the 2013 trucks and should have put the 4.5 duramax in the halftons that got 30 mpg)

I would get the vortec get a good cam OR if you want a LS2 LS3 call up scoogin dickey get a set of off the shelf LS3 heads put them on the 6.0l block carb intake and LS6 hot cam and you have a 450 hp reliable motor for around 2500

 

What would the torque curve look like for that??.

 

http://www.superchevy.com/technical/...p/viewall.html

with dyno numbers

 

Yep-I read that article when posted before.Not much info about below 4 grand.Is there a way to get the numbers up below 4 grand??.

 

That would be an interesting build, wonder what the numbers would be if fuel injected? But that build would be more towards my budget too

 

So as more reading I have done on this forum, I come across a couple of theads involving the 4.8l vortecs, so I kinda wonder what these engines can do, soposedly their the same engine as the 5.3 but a shorter stroke, and I can find them cheap around my area, 400 to 750 for a compleat block

 

If you decide on a 4.8, my buddy in the Kalamazoo area has a good 4.8 out of his 02. Ran great, just pulled it for a blown lq9. He'd sell I for 350

 

I might have to do that, that's only about an hr or so drive from me, I have been getting some parts for my 89 from a guy in PawPaw MI

 

That would be Brandon, he is a great guy, my best friend, and my best man when I get married in June. Met him several years ago buying parts when I was beginning to build my 92.

 

Tht would be him! Ya I got a 5.7 tpi and 700r4 from him last year an. Now I decides that I'm gonna go another route, with an LS block instead, ya he is a great guy

 

I would at least put a 6.0 in it. I just pulled the 5.3 out of mine in favor of a lq9 6.0 (H.O. 6.0) and i wish i would have done it to begin with. The 5.3 wasn't a turd but the 6.0 is a beast compared to the 5.3 . I don't think i would ever throw a 4.8 in a car unless it was the wifes car or if i planned to tape a hair drier to it later. But i promise you will be really happy with any ls engine. They are tuff and get good MPG.

 

Put it this way, a goal of 350-400 rwhp is what I'm looking for, with the 4.8 with their small stroke and low compression, they can take a turbo well from what I have been reading, I could figure on streanghing the lower end, put a decent cam in it, then run it till I can get money around for a turbo, I also plan on bolting a T56 up to the block aswell

 

There is not really any point in touching the bottom end in these motors. Its also going to take some $$$ to get 400 rwhp out of a NA 4.8

 

That is true....ah we'll I'm still pondering on what engine to use anyway.