Help me decide... 383 or LSx?

[AK49BWL]

Based on what your driving style are, I'd stick with whatever is cheaper. Machine work in not inexpensive, so a LM7 swap is likely going to be cheaper. The LS are going to have to rev more, but they make higher HP and are very inexpensive.

I'd also look into 4L80e swap while you are there. The 5.3/4L80e was offered in the early GMT 800 2500LD regular cab and some 2500/3500 Express Vans.

My Sierra is currently a manual, and will be staying manual. I've always loved shifting myself.. I do have my Blazer's 4L60E shifting pretty well the way and where I want it to, but it took a lot more time for trial and error to get right than it would have taken if I'd just had a stick in there lol. And I really...don't like torque converters.

I'm surprised you say your Dad's suburban 2500/6.0 is slow. I just bought an '06 same engine and it feels considerably faster than my 3500 CCLB SRW 5.7. The truck is heavier, but not by much. Either are heavy and not super fast compared to any 1500, though.

The suburban 6.0s had higher HP ratings than the 2500HDs, probably because the they figured the trucks were going to be used for work vehicles and detuned them more.

Like I mentioned, it may just be that particular truck. When he bought it, a few weeks later he literally blew the muffler off (blew it in half actually) because the idiot previous owner put on a terribly restrictive muffler that was seriously too small for even a 5.3, much less the 6.0. It woke up a little after he got an OEM-style muffler put back in, but it still feels weak to me. Probably something else going on with it... He's had nothing but issues with that truck. But, that's the only 6.0 truck I've driven, so I probably shouldn't even use it as a basis for any decision lol.

4.3 swap?

jk

For sunk costs, I'd go with the 383 or a straight up 350 and build something else with a 6.0 if you feel froggy.

I have thrown that idea around some, just build lightly on the Sierra, and drop a 5.3/T56 combo in the 2wd Blazer for fun/speed demon-like stuff because I do get, as you say, "froggy" sometimes haha..........honestly, I wish I'd done that when I bought the Blazer, because the 4.3 in it had to be rebuilt not long after... P/O killed it pretty bad. But eh. It's my "good gas mileage daily driver truck" that gets up pretty good and does 24mpg highway right now lol.

 

[OutlawDrifter]

Where to start....

The LS platform without boost will never build the low end torque that a SBC will, without serious cubic inches.

They are different animals. LS/LQ engines need RPM to make power, and they are seriously hobbled from the factory with torque management and terrible fueling/ignition tables.

I love LS engines, my '91 Z28 and '49 GMC both have 6.0's. LQ9 based in the Camaro and LQ4 based in the '49. Your dad's burb feels slow because of the heavy handed 4L80E (not to mention it's terrible 1st gear) and the piss poor factory tuning.

At one time I had a 6.0 powered 2010 2500HD that would flat get with it(after a tune)...but it had the 6L90E with better basement gears.

In your case...I wouldn't even worry about the extra cubes (383) or going LS. When you're ready, punch the block .030 over and put in the RamJet/Marine 385 cam, some awesome exhaust, and call it day. If you really want to get into it, spend some money on a FIRST TPI, HSR, Edelbrock Pro-Flo, or another intake that will maximizes the torque, and some aluminum Vortec (or whatever flavor, don't go too big, keep that velocity up) heads and let that thing eat.

The LQ9 in my Z28 has a 230/232 duration cam, .585/.595 lift, LS6 car intake, and puts 425rwhp down. This is through a T56 and Dana 44 rear. I think the original TPI L98 5.7l would keep up with it to the next stop light....but when I hit 2700ish in the new setup and rip the next gear at 7000rpm...wow...just wow. Not practical for a heavy 4x4, but it is wild.

On your transmission front...if you're not abusing it and getting extreme traction (ergo clutch dump at 3500rpm+ and pulling the front left tire)...run it until it tells you otherwise.

One build that I want to do before I hang up my spurs is a new Blue Print Engines Gen 1 SBC 400 block, good aftermarket aluminum heads, FIRST TPI, coil on plug ignition with the 411 ECU. 10.0:1 compression to keep it pump gas friendly, and a nice RCSB GMT400 wrapped around it...at this point I don't even care if it's 2wd or 4wd!

Then I'd like to swap in an LS7 427 just to see how different it is....

 

[2001ZR2]

I’m In favor of 383 T56 combo but that would kill your budget. NV4500 maybe

 

[AK49BWL]

Eh, budget smudget lol. T56 won't mate with an NP241 anyway.

I'll be honest, I actually expected more to be in favor of the LS/LQ. To be even more honest, I myself was leaning more toward just building on what I have rather than going with a totally new setup, but I'm sure y'all know how those little nagging ideas tend to break in lol

I'll probably hang onto the 3500 until it breaks.. When it does, go 4500. The 3500 in there is solid, smooth-shifting and tight still, even with 217k on the clock. Would be a shame to not get all I can out of it. I can't put it in my Blazer because it's a 2wd and the truck is a 4x4, or I'd go that way with it lol.

 

[Geoff Walliser]

Here is a great recent article on a 383 vs 6.0 LS.

https://www.speedwaymotors.com/the-toolbox/project-chevelle-383-vs-ls-shootout-tech-article/30217

You can't go wrong with either, but I voted LS. I like the multiple fuel injection options, oem ignition setup, still evolving after market goodies, and boosted potential. Plus cammed junkyard motors make built SBC power.

I've found two truck version 6.2s (l92, L9H) engines both for less than $3500 Canadian. Those start you out at 403hp stock.

Looking forward to whatever you decide!

 

[ZRoe]

I voted to keep the 3500 until it dies. There is a gentlemen on the forum that goes by L29sub that ran an NV3500 behind a lightly massaged 454 with a carb in his k2500 Suburban and it did fine, evening for towing. Though he did admit it was the weakest link in the drivetrain. He liked the smoothness of the 3500 over the more truck like shifting 4500.

The fuel injection options would be the only reason to jump to an LS style motor in my opinion. I actually have a Vortec 7400 so I already have 8 independent injectors so no real reason to LS swap my truck once I finish the 0411 swap. Only two crazy options are in my mind; if the cam fails but the motor is salvageable I'll throw in a bigger cam and injectors and maybe eventually some forced induction or if the cam kills the block I might go to a Duramax and try and find the elusive ZF6 that bolts up to it.

With that said, I think the ZF6 that bolts to the 8.1 Vortec also bolts to the Duramax and may even bolt up to the smaller LS variants since GM autos seem to cross between big blocks and small blocks pretty easily (4l80 swaps into 4l60 trucks come to mind). That is just a naive/hopefully ASSumption on my part though, still worth some research though.

 

[Supercharged111]

Eh, budget smudget lol. T56 won't mate with an NP241 anyway.

Yeah it will.


https://www.motorator.com/blog/gene...zilla-tremec-6-speed-conversion/#.XqRtZVNMFaw

Rockland's site wasn't working for me. Also, you should take LM7 off of your list.

 

[BNielsen]

383/NV4500 just sounds cooler in my opinion.

 

[LVJJJ]

I voted for the 383 stroker as I just replaced my dog of a 350 with a remanufactured one in my '94 K1500 from S&J Engines of Spokane WA only $2300. The torque power is amazing, tows our travel trailer with no problem. Can even tow in 4th on the more level roads. I did have a Roadtrek Class B Motorhome with the 6.0 and it was a great engine also. The 383 just drops in and everything hooks back up real easy. Best improvement I've ever made to any of my vehicles except for putting a 292 in my 65 Chevy Van.

 

[L31MaxExpress]

8.1 and NV4500 gets my vote.

 

[AK49BWL]

Yeah it will.

O_O well ain't that something. Not that I need another crazy idea lol