Re: 383 or 5.3?????????
 

Re: 383 or 5.3?????????
 

WOW!

If in the future I had the funds, I would swap out my straight 6 cylinder for the LS motor and tranny. These things are so tunable and reliable and great on fuel mileage if you keep you foot out of it. :lol:

But over all just a great alternative vs. a crate motor!

Re: 383 or 5.3?????????
 

Yeah, and you gotta deal with opti-farce too. My mom's 94 t/a m6 sure ran good, and one will get great mileage plus has the roller cam and the advantage of compression and decent heads over a gen 1. I would only get an lt1 if I came upon a deal. It's hard to beat a 6.0 for 700$ or so... And all of this talk about burnouts, it's a light truck and none of the weight it has is on the back??? I know y'all are just messing with each other though... With a good tune and the 2004r/ 4.10 gear set up I want, I could burn em down all day with my stock 350. It pulls a mean one wheel peel now though :lol:

Re: 383 or 5.3?????????
 

I've been reading this thread from the beginning and chimed in once before. I still vote for the LSx swap over a gen 1 of any size. To the Original Poster: From what I have noticed on this forum in general is that 90% of the people who bash the LSx swap because it's too "expensive" or "will take a year to get it running" have never actually done the swap. So don't let them sway you away if you think you might want to do it. I guarantee you will not regret it!! And as long as everyone keeps bringing up "$2500", that will also build you a bullet proof 408" LS short block. The sky is the limit then on the power you could make and you'd laugh at any 383 you came across. I realize that's not a running motor for that price, but still not too far off. So if your serious, just ask some guys that have done it, we'd be happy to help. I can be done very cheap and is not hard at all.
Another thing for you budget minded guys. You don't have to run a new radiator and electric fans. I'm using the stock radiator with new fans, cost about $60 for both, but you could also just use the mechanical fan that came on the 5.3 or 6.0. Another cheap trick is to use an in-tank pump with your stock tank. My 255LPH was only about $80.
Just some thought....

Re: 383 or 5.3?????????
 

And from everything I've read in these posts, those bashing Gen 1's saying they are too bad on gas, or they don't run as good, or, they don't last very long, in my opinion have never owned, designed or tuned a Gen 1 properly.
:lol:

Re: 383 or 5.3?????????
 

A gen 1 anywhere near the power level of the lsx motor will never make the same mileage though

Re: 383 or 5.3?????????
 

I will alway have a fondness for gen 1 motors.....I grew up with them, but it's hard to beat technology. When you can get over 600 hp on pump gas (ZR1 Corvette) and still have great street manners and still pull down +20 mpg if you're easy on it.......how could you ever argue with that? Yeah, that's big money but still designed around the same LS platform. you could easily get that power from a gen 1 motor, but side by side.....which one would you rather have. At the end of the day, it's just about personal preference and what you are most comfortable with.

Side by side it also seems obvious to me that the LS style motors will go many more miles before wearing out and the main reason I see for that is fuel distribution. Port injection with high pressure injectors is just better at distributing fuel than carbs and this is just better for cylinder walls.

That all said, I still have my mini supercharged 383 in mine and I will have fun with it for a few more years (maybe less) before I do a late model swap......love to do a 6.2 with radix (or similar) on it.

SO.....let the battle rage!

Re: 383 or 5.3?????????
 

Just out of curiosity, Jim PA, do you agree with '72customdeluxe? For example 2 motors both making 400hp.

Again I am not a motor builder nor have I installed either of these motors in my truck, but I do have a genius level friend and we had a discussion a long time ago about the new LS motors. As I recall we were comparing why a motorcycle motor makes more power on less displacement and runs on pump gas. I think that was the convo, anyway, he said the problem was heat dissipation. The newer gen motors run way cooler therefore more efficient. I assume that will play into '72customdeluxe's statement. If I am wrong please chime in.

Re: 383 or 5.3?????????
 

Yes, but I think you could make the mileage close enough that it shouldn't be a deciding factor. My build should be in the 390-400 range, and with an overdrive, I'm confident I could easily get 17-18 with it.

I also take into consideration that my 04 yukon has averaged 14.5 MPG over the last 4 or 5 tanks of gas. I've never seen more than 17-18 MPG on a highway trip with it. I realize it weighs about 800lbs more than my truck does.

I'm not anti LSx. I think it's a cool thing to do, and if 5 years ago when I started with nothing under the hood and had it been as economical and common as it is now, I would have considered it. But IMO, the entire requirements bill for an LSx swap over-complicates things, and would make back-yard tuning and diagnosing problems less more difficult than staying "old school"...

Re: 383 or 5.3?????????
 

I agree with what you are doing. I see 17.5 mpg regularly in my 06 SWB 2wd and that is at 80mph highway and beating it around town. I have seen 19.5 mpg when I do strictly highway at 65mph and under. I am 4200lbs curb weight I believe. I am surprised you get such poor gas mileage from your 04. My brother in laws 02 4 door 4wd gets 21mpg average. He drives like a grandma.

When I see guys pull off the 5.3 swap at $1500 complete with doing all the labor themselves I find it hard not to be an advocate. I also see my friends tune their FI motorcycles from their laptops on a regular basis, so I can't agree with your backyard tuning, but I can agree it may not be for you. I can tune my truck with several products out their that cost as little as $200 (I think, been awhile since I looked at the handheld stuff) so you don't even need a laptop if you maintain the data port with the factory computer.

That is where I am coming from. Plus you can than add heads, cam, etc.. to get you into 400-500hp territory.

I looked into supercharging my 5.3 and I was told my stock motor puts down 220-230hp at the wheels and with a magnacharger would be about 450hp at the tires (with a 3 year warranty). I spoke to another tuner who said I would be better off with a centrifugal blower that would net me well over 500hp at the tires and that they had a GTO with an LS2 stock block with water injection at almost 750hp at the wheels and there wasn't any issues with reliability. That also makes me an advocate for the newer gen stuff.

Re: 383 or 5.3?????????
 

One thing about tuning and diagnosing problems: With the LSx engines, since they're all computer, you will get an error code that you can read using a computer. If you get the tuning program you can read and clear all of the codes as well as tune the fuel and timing much like you can with a carb and distributor (but without getting you hands dirty). If you're using a 4L60E or a 4L80E you can also tune the shift points, line pressures, and other things.

Learning to use the tuning software isn't really tough. It takes a little bit of reading and understanding basic engine operations. You get a lot of information to base your changes on. Unlike tuning a carb engine where you basically have your ear and seat of your pants. You just can't tune accurately in that way. (Yes I know you can go put the engine/truck on a dyno and tune more accurately, but do people do this a whole lot on a non race vehicle????? Probably not.

Customizing the stock harness to work isn't real difficult, and again with the tuning program, you can turn of the vats system yourself.

Oh, one other thing to mention
With my 72 GMC LWB (~4000lbs) with a nearly stock 350 TPI and 700R4 (~270HP) I got a best of 18mpg. A fuel injected 383 will get less than that and carb probably even less. My 05 4x4 crew cab (~5600 lbs) with a 5.3L has gotten a best of 22mpg (oh and it makes ~300HP)

Re: 383 or 5.3?????????
 

By backyard, I meant hammers, screwdrivers, timing light, vacuum gauge, etc.

It's right up my alley, computer programming is my profession. Maybe that's why I don't want to deal with another one in my life :lol:

Re: 383 or 5.3?????????
 

I don't see how you can be so sure of yourself. Fuel mileage isn't necessarily a factor of displacement. It's about efficiency.

Re: 383 or 5.3?????????
 

Both being gen1 engines, the efficiency of each is about the same. But generally speaking the 383 will pull in more air (more displacement) and then more fuel to have a good air/fuel ratio.

Same thing holds true with the 5.3L vs 6.0L. 5.3L will be more fuel efficient.

Re: 383 or 5.3?????????
 

Same thing holds true with the 5.3L vs 6.0L. 5.3L will be more fuel efficient.[/QUOTE]


Depending on gearing you can get better mpg out of a 6.0. My dad had a lq9 in his 69 camaro with 3.73's and my brother has a ls1 in his 69 camaro with 4.11's. The lq9 would get about 23mpg and the ls1 would get about 19-20mpg. Then the lq9 would out run the ls1 even with 3.73's.

Re: 383 or 5.3?????????
 

I guess I left out, "all other things being equal"

Re: 383 or 5.3?????????
 

LOL...I was just throwing that out there to compare. These cars are 6 speeds though and that is where the mpg comes to play on them;)

Re: 383 or 5.3?????????
 

My LS1 6 speed vette got 33mpg (and ran 12.18 :D)

Re: 383 or 5.3?????????
 

I just wish I had a ls1 6 speed vette, I wouldn't care about the mpg:lol:

Re: 383 or 5.3?????????
 

Thanks for all the replies, I had no Idea that this was such a hot topic:

I decided to go with the 383, and before you say anything, read my reasons.

1. Love the old-school look, in my opinion, a smallblock just looks better in my engine bay.

2. I have a good 700r4 with less than 1000 miles on it that I want to keep. IMO, a LSx swap would be much easier with a th400/350 or a 4L80/60, the 700r4/2004r tv cable is too sensative, and it sounds like a lot of trouble to fabricate up a bracket. plus, I run the risk of burning up a $1300 transmission.

3. my truck has been down long enough, a LSx swap will burn time, I WANT TO DRIVE MY TRUCK THIS SUMMER.

4. SIMPLICITY, I like to keep my truck as simple as possible. the 383 is simple in terms of wiring and tuning

before I go any farther, I must mention that I am a computer geek and the wiring and computer tuning do not bother be at all, As a matter of fact, I'll probably do an LSx swap in the future on something. (probably a 3rd gen camaro)

I think that the LSx and the 383 are both very strong motors that can both make some serious horsepower. but in my case, 383 is the engine of choice.

as far as mileage, I think a LSx might do better, but mileage is not one of my concerns, the 700r4 is there for my mileage

some of yall may not like my choice, and I may regret it later, but I just think the 383 is cool in an old school truck. I'm not bashing the LSx, but its just not right for my truck.

THANKS FOR THE REPLIES.

Re: 383 or 5.3?????????
 

You have made the right choice.... The one YOU want. That being said I have decided to go with an lsx swap with project cod fis instead of a 572. I got a good deal one one and decided to sell it and take the money and do an lsx swap. I think it will make for a better long term ride that I can go to California in and not worry about driveablity and the price of GAS

Re: 383 or 5.3?????????
 

Here are some nice trucks with ls swaps.


http://ls1tech.com/forums/conversion...-383-swap.html

http://www.racingjunk.com/category/1...ry-slick-.html