GM Vortec Engine Expert, Late 90s

"Rusty Vandura - www.tinyurl.com/keepoppo" (rustyvandura)
05/27/2016 at 14:39 • Filed to: None

I want to swap the 4.3L Vortec V6 for a Vortec V8. I am told that certain of the Vortec V8s will bolt directly in place of the 4.3L.

The vehicle is a ‘97 GMC Safari.

Can anyone speak to this?

DISCUSSION (42)

Smallbear wants a modern Syclone, local Maple Leafs spammer > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 14:42

I believe this is correct. Iirc since the 4.3 is just a shortened 350 it uses the same engine mounts.

But better still get confirmation because I’m not 100% sure.

HammerheadFistpunch > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 14:44

The Vortec 4300 will interchange with the Vortec 5700 for sure, likely anything with the LS engines as well.

HammerheadFistpunch > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 14:51

This seems like a good place to be

http://astrosafarivans.org/bb2/viewtopic.…

You can do the 5.7 swap easiest, and the 5.3 is doable, though harder. You’ll obviously want to also visit overlandvans.com

http://www.overlandvans.com/0104_liftkits.…

Dave the car guy , still here > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 14:51

There is a forum AstroSafari.com that has a sub forum for a V8 club. You might want to lurk there to see whats involved. I’d bet you have to eliminate engine fan and clutch for clearance and move to a front mount pusher fan for cooling.

Rusty Vandura - www.tinyurl.com/keepoppo > HammerheadFistpunch
05/27/2016 at 14:51

The guy who got me started thinking about this said he swapped “a 350.” I am hoping to get specific, and to fine an engine with an aluminum block that will fit. Then install an 8-inch rear end with posi and do a little bit of drifting.

shop-teacher > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 14:53

The 5.7 is pretty much a direct bolt on, because the 4.3 is literally a 5.7 with two cylinders chopped off. With LS engines there’s a lot more to deal with, as accessories and mounts and whatnot are different.

Rusty Vandura - www.tinyurl.com/keepoppo > Dave the car guy , still here
05/27/2016 at 14:54

A guy I know made the swap and the van is for sale, but it’s 4WD. Wanna drift...

HammerheadFistpunch > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 14:55

Aluminum? Hmmm, I think any of the gen II SBC will work but I can’t say. The Vortec 5700 which is the easiest swap is Iron. You can find aluminum versions of the 5.3 which might make the most sense. You can buy complete engine harness from painless for the 5.3 and that could aid in your install if there are problems there. Here is a writeup on the LM7 swap

http://www.astrosafari.com/viewtopic.php?…

Rusty Vandura - www.tinyurl.com/keepoppo > shop-teacher
05/27/2016 at 14:56

Thanks. This is where I want to dial in. Would we be talking Vortec 5700? Do you think I could find one with an aluminum block?

unclevanos (Ovaltine Jenkins) > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 15:03

If you’re getting a used l31 5.7 vortec they are all iron blocks. You can shed weight with aluminum heads if you want.

itschrome > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 15:04

v8 swap. Yawn.... BUILD OUT THE 4.3! somethign like this:

http://www.hotrod.com/how-to/engine/…

there’s a bunch you can do to those things but this has a cool out line for a huge build. haha but built 4.3 is soo much cooler than v8 swap.

shop-teacher > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 15:04

I’m not aware of any aluminum variants of the Vortec 5700, because Vettes and Camaros had LT-1s and then LS1s. I suppose there could be some weird rare version, but if it exists it’s gotta be very rare.

Rusty Vandura - www.tinyurl.com/keepoppo > unclevanos (Ovaltine Jenkins)
05/27/2016 at 15:07

Any idea what the weight difference would be between the 4300 and 5700?

Rusty Vandura - www.tinyurl.com/keepoppo > itschrome
05/27/2016 at 15:09

I wouldn’t be opposed to that at all, but it would be much costlier and dependability could be an issue.

Rusty Vandura - www.tinyurl.com/keepoppo > shop-teacher
05/27/2016 at 15:10

I’m told the 5700 is the cleanest swap option. I need to look up some specs.

Rusty Vandura - www.tinyurl.com/keepoppo > HammerheadFistpunch
05/27/2016 at 15:10

I think that would be too complicated for my interest level.

shop-teacher > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 15:12

It definitely is, because it will bolt right to the transmission, and all the accessories will bolt right on as well.

HammerheadFistpunch > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 15:12

yeah, just grab a 5700, swap the heads and call it solid.

Rusty Vandura - www.tinyurl.com/keepoppo > shop-teacher
05/27/2016 at 15:17

Can you help me to find more specs on this engine? I’ve looked on Wikipedia, and the information there is confusing. I’d like to find the engine code, mainly: LMx, LTx. Then I can look up the performance specs.

shop-teacher > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 15:39

Hmmmmm. If you can find the archives online for Hot Rod/Car Craft/Popular Hot Rodding/GM High-Tech Performance from the late 90's/early 2000's, I bet they’re in there somewhere. I’m not fully versed on engine codes.

Or check GM truck forums.

Manwich - now Keto-Friendly > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 15:56

The 4.3L engine is basically a V6 version of the 1992-1997 LT1 V8.

https://en.wikipedia.org/wiki/Chevrolet…

Now I have two crazy ideas... first, a crazy-awesome idea... swap in the DOHC 32v Corvette LT5 engine:

https://en.wikipedia.org/wiki/Chevrolet…

..and a crazy-stupid idea... swap in the the LT1/L99 engine:

https://en.wikipedia.org/wiki/Chevrolet…

The 2nd idea is exceptionally stupid because you would go through all the trouble of a swap, add weight, only gain 10hp and LOSE 5 lb-ft of torque.

Manwich - now Keto-Friendly > itschrome
05/27/2016 at 15:57

How about BOTH? Do a V8 swap AND build out a 4.3?

https://en.wikipedia.org/wiki/Chevrolet…

:-)

itschrome > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 16:02

Fair enough. My buddy did a built out of his S-10 SR2. added a cam, port polish and a fuel remap nets him 221HP at the wheels and something like 250 Torque. before he was showing 173 HP at the wheels and like 230 torque. that little change and it’s a damned beast of a farm truck.

I Will Always Be The Honey Badger > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 16:09

Find a ‘96 or newer 5.7. They make 255 stock, and just a cam/intake/header build will have you well into the 300s on a mostly stock longblock.

TheJMan92 > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 16:20

I’m not sure about the cost front, unless you plan to buy a running V8 vehicle and swap everything out of it. Even then, messing with the ECU and all can be a pain.

Rusty Vandura - www.tinyurl.com/keepoppo > Manwich - now Keto-Friendly
05/27/2016 at 16:23

I’m having some trouble narrowing down precisely what V8 I’m talking about. The fellow who got me thinking about this said, “No, not the LT-1.” He’s a guy who’s done a number of swaps, but he may have misunderstood me. And I’m hearing differing nomenclatures between “Vortec 5700,” LT-1, et cetera.

TheJMan92 > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 16:23

These should get you darn near everything you want. Signed: Another person thinking of an LS swap when the Benz finally blows up.

http://www.superchevy.com/how-to/0901gmh…

http://www.camarotech.com/engine-LS.html

Rusty Vandura - www.tinyurl.com/keepoppo > I Will Always Be The Honey Badger
05/27/2016 at 16:29

What would the engine code be on that? LM? LT? LS?

Rusty Vandura - www.tinyurl.com/keepoppo > Manwich - now Keto-Friendly
05/27/2016 at 16:31

When I look at that Wikipedia page, I get really confused.

I Will Always Be The Honey Badger > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 16:59

That would be an L31.

Rusty Vandura - www.tinyurl.com/keepoppo > I Will Always Be The Honey Badger
05/27/2016 at 17:29

Perfect. Now I can begin researching.

Rusty Vandura - www.tinyurl.com/keepoppo > I Will Always Be The Honey Badger
05/27/2016 at 17:36

If all I want to do is drift in an Astro van, then wouldn’t the stock L31 be adequate?

Rusty Vandura - www.tinyurl.com/keepoppo > I Will Always Be The Honey Badger
05/27/2016 at 17:38

Do you know the corresponding engine code for the 4.3 V6?

unclevanos (Ovaltine Jenkins) > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 17:39

Not much I’d guess the fully dressed 4.3 is 75% the weight of a chevy 350.

I Will Always Be The Honey Badger > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 17:41

Yes it certainly would. But I can`t resist adding a little more power while I`m at it.

I Will Always Be The Honey Badger > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 17:45

I`m pretty sure it`s an L35 on your year van. If you`re not sure, run the vin through www.17vin.com . That usually gives you a full list of your van`s build sheet.

Rusty Vandura - www.tinyurl.com/keepoppo > I Will Always Be The Honey Badger
05/27/2016 at 17:45

When I poke around online, I see L31 and L31-R, with a difference being mentioned about 1/2-ton versus 3/4 to 1-ton trucks.

Just wanna drift. I have a ‘97 Safari that I’ve updated all of the suspension parts and it drives really well.

Rusty Vandura - www.tinyurl.com/keepoppo > I Will Always Be The Honey Badger
05/27/2016 at 17:48

How much weight do you think I would be adding? Would I need to beef up my front springs any?

Rusty Vandura - www.tinyurl.com/keepoppo > I Will Always Be The Honey Badger
05/27/2016 at 20:25

It looks like the 4.3L engine would be rated at 180 HP. The L31 is 255 HP. That’s a nice bump, but I think it really needs to be closer to 300, to make the effort worthwhile.

Manwich - now Keto-Friendly > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 22:56

Well if it’s anything older than the 350 cid V8 from 1992-1998, I wouldn’t bother doing the swap. A lot of the 350 cid V8s from the 1980s and older make about the same or less power than the 190HP in the 4.3L you already have.

Rusty Vandura - www.tinyurl.com/keepoppo > Manwich - now Keto-Friendly
05/27/2016 at 23:04

Agreed.

I Will Always Be The Honey Badger > Rusty Vandura - www.tinyurl.com/keepoppo
05/27/2016 at 23:58

Yeah I’d be looking at a bigger power increase then that for the work and money involved. If all you want to do is drift, do some exhaust work for better sound (because half the fun is bouncing off the Rev limiter sideways), a limited slip or locker, and go burn off a few sets of tires.