All too common LS swap vs unique old school small block

[L31MaxExpress]

GMT 800 Tahoe? That looks like a GMT 400 to me. But you are right, the early GMT 800 trucks in the Mexican market still ran the L31...and manual is more common down there. The Mexican version of the Silverado is called Cheyenne.

The I6 from Brazil? I remember that white truck. IIRC he was from Argentina or somewhere down there...

That one is a GMT400. I have also driven a GMT800 with a 350. The 350 was through 2007 down there. My P59 tune in my van started as an 05 Mexican L31 truck.

 

[L31MaxExpress]

This is a diesel Grand Blazer aka Tahoe. Extremely reliable and approaches 30 mpg highway from what I hear.

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[stutaeng]

Ok, gotcha.

 

[L31MaxExpress]

This is an all factory TBI 250 I6 in a GMT400. This one had a 4L60E or possibly 4L30E behind it. The owner said it was the light duty 4spd electronic auto. The Opala 4100s use the 4L30E. Think Isuzu Rodeo or Cadillac Catera trans. From what I remember this was a 1995 or 1996. Notice it has the driverside fusebox that came into existance in the 1995 interior upgrade.

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[Erik the Awful]

This is a diesel Grand Blazer aka Tahoe. Extremely reliable and approaches 30 mpg highway from what I hear.

What engine is that? Caterpillar? John Deere? I've seen that saw-tooth valve cover before, but I can't remember where.

 

[stutaeng]

Looks like it's manufactured in Brazil: MWM 4.2L Turbo Diesel.

MWM International Motores - Wikipedia

en.wikipedia.org

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[langkg]

I don’t understand all the dislike for SBC. The LS transplant requires a lot more modifications to complete including your AC and PS hoses whereas you can bolt in a 383 and Sniper (or EFI of your choice) with fairly simple wiring and a new fuel pump and make more power than a even a 6.0 or stock 6.2. Sure either engine can be built to the hills but what’s the end goal? I have a dyno’ed 383 / Sniper with relatively mild cam making 425/475. What more do you need? It looks fantastic in the engine bay unlike a lot of Frankenstein LS swaps I’ve seen. Granted there are plenty out there that are done right and look professional but there is a ton of stuff just slapped together. In the end it goes back to how much time and money you want to invest but doing a mild build 383 with aftermarket EFI is pretty simple and effective.

 

[Erik the Awful]

I'm a 350 fan, but the LS has a higher top-end capability from the factory, from 2-bolt vs 6-bolt mains to .480" vs .600" lift and better heads. That said, if you're not boosting, and you're doing truck things, a 350 can be built - cheaply - to do as much as a *stock* 454 or 6.0.

A junkyard 5.3 with a turbo is cheap power, but once you embark on rebuilding that motor, you're throwing down more cash.
A 6.0 can compete with a 454 on doing heavy truck stuff, but the 454 is the king of torque. Both will set your wallet on fire.

 

[stutaeng]

Did OP ever chime back in?

Since no one mention the "power under the curve" theory, I was looking for HP & TQ curves for some of these engines...Not much out there on the web for the older engines, unless someone is hot-rodding their souped-up engines and throwing it on the dyno.... I was trying to compare stock vs stock.

Anyways, I did a quick PDF scaling of a L31 vs a LS2 (Edited to LQ9.) This is obviously an very unfair comparison, but that's what I found... Choose your engine and plug in your own curves for comparison. (or do your own dyno runs, )

I'm just trying to show the HP and TQ curves for each engines. I graphically scaled the RPM scale and the HP scales. I brought down the TQ curve on the right graph because the HP/TQ scales are different on each graph. So compare the red & blue lines...

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I'm obviously no expert, but I seem to recall the curve that yields the largest area under it on the HP is the one that has more "power," from a theoretical perspective. Up that point, I understand that concept. I get lost when you start introducing gear ratios and what that does the curves...

Dang, now I feel like a Richard Holdener, LOL.

 

[0xDEADBEEF]

The LS2 has more displacement, more torque, and around 1500 extra useable rpms, it can't lose. Not to mention it's all aluminum and weighs ~100 lbs less.

The L31 makes it's peak torque lower, some people love that. I don't believe in the torque monster myth.