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Discussion Starter · #1 ·
A friend of mines has a 1997' GMC Yukon with a 350 L31 Vortec motor.He just aquired a 98' Suburban with the 454 L29 Vortec motor in it.He wants me to swap the 454 in his Yukon.
What do I need to do?
Will we have to worry about smog police?
Thanks again.
 

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Thats not a simple task. Sounds to me like a project on Monster Garage. I'm not saying it's impossible and I dont know your skill level. New vehicles arnt as simple as the old ones you can't just swap motors and trannys and hook up the fuel and wiring and expect everything to work out. The tranny from the 350 might work, but things like engine space, engine mounting and most important electrical wiring are gonna be a huge snag. If he's looking for more power your best bet would be mod the 350 and leave everything alone.
 

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Some Punk Kid
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Physically swapping the motors would be decently hard but very doable.
Your problems will be with Electronics/Computer/Sensors.
Something you may want to look into would be the size of the gas tank. That suburban should have a 42 gallon tank. The Yukon should be a more standard size 17-25. They put that extra 20 gallons for a reason. 454s have a drinking problem.
 

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Car? Truck? Who Cares
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I would think---Being essentially the same frame and body, should not be that hard.

Engine-trans-and all computers/wiring would need to be swapped.
Get hold of an actual GM manual on that car and do some looking.

Probably won't get any better performance out of it though.

The Suburban----3/4 or one ton??? Stump pulling, RVtrailer and ATVtrailer dragging, family of 8+ luggage, I-pods, and teddybears. pack wagon


Any way---I would think, basically a bolt in and go----may have some reprogramming of the 'puter for tire size and gear ratios.

Bryan
 

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Discussion Starter · #5 ·
I was'nt sure But I thought it would require using the suburban harness and computer,Making new exaust,and modifying motor mounts?I could be off im not sure.But he wanted to swap for performance sake.I just dont know what you can really do to a new motor,that wont affect the computer or smog testing.
 

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You can easily use the 1997 PCM, you will need to get a 454 calibration installed..

Are you using the stock 350 4l60e or will you be swapping in the 454's 4l80e?

If you intsall the 4l80e, you will need to accomodate the 4l80e's extra speed sensor, and aslo correct the shift strategy via PCM programming.

The Vortec 350 L31 is rated at 255 hp and 330 lb/ft torque, the Vortec 454 L29 is rated at 290 hp and 410 lb/ft torque.

the Vortec 454 uses a larger exhaust than the Vortec 350. i suggest Hooker Competition headers. You will need to weld 1 O2 sensor into each header collector. You will need to either install catalytic converters or delete the rear O2 sensor reporting via PCM programming. The rear 2 O2 sensors tell the PCM if the cats are there and functioning properly. I assume

you have the 454 truck sitting there so all the parts you will need are there.
If you dont like headers use the manifolds from the 454 along with the headpipes and cats from the 1998 vehicle. Then yuu just screw in your 2 precat and 2 post cat O2 sensors into the 454 exhaust.

PCM tuning can be done by Fastchip, PCMforLess or Wait4MePerformance.com.

fastchip did the PCM tuning for my truck. You will need to tell them EXACTLY what you are doing here. PCM tuning will wake that 454 right up.

this swap is a bit of work, but is by no means unattainable.

The 4l60e trans wont like the 454 for very long. you can get a 4l60e rebuilt to easily take the stock 454 Vortec.
While the engine was out, I owuld be sticking a perfgormance cam in that 454. The Vortec 454 uses a 24 lb/hr injector, the 350 uses a 19 lb/hr poppet injection system. The injection in the 454 is superior by far. teh Vortec 350 uses injectors that limit power to 400 hp. these injector cannot be replaced by larger inkectors unless you use a different intake manifold. I am using a Merc Marine intake in my Vortec 350 with 29 lb/hr injectors.

If you have any questions, post back You are basically doing what GM should have done.

When you get a smog check, do you have to pass a visual? do they hook into the OBD2 connector under the steering wheel? Do you do an exhaust test??

peace
Hog
 

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Discussion Starter · #7 ·
His smog guy only does the pipe test,from what he tells me.Thanks the info really helps.He wanted me to do the project for him.I told him He would have to wait till I could figure out if I could do the swap.He will probably use the motor and trans all together.
Do you think it will fit with out much trouble?It looks big enough.Also do you think the wiring harness(Engine harness) will plug in as one assembly?
Thanks for your help I really appreciate it.
 

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Sir, that is California. Or did I miss something?

You put that engine in there and the VIN won't match the engine installed. It will have to pass the smog for the age of the vehicle.

What if the "smog guy buddy" dies or something.

You might get that thing swapped and never be able to drive it again.

Since you asked, I think it is pretty much a mechanical bolt in, who knows about the FI wiring.
 

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Yeah cALI WOULD BE ALMOST IMPOSSIBLE TO SMOG THIS SWAP, IT COULD BE DONE THOUGH.

This would be a good swap, but I wouldnt be putting a stock L29 in it, It would be going in with a cam and some smoothing in the heads and intake, longtube headers and exhaust.
An agressive 94 octane PCm tune would work nice.
peace
Hog
 

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Old(s) Fart
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Actually, Califorinia is one of the EASIEST areas to do swaps, because the ARB has a documented approval process specifically for engine swaps.

The rule of thumb is that you can always put a newer engine in an older vehicle so long as you transfer all the emissions equipment and controls that go with the newer engine. Putting a 98 motor in a 97 vehicle is allowed in Calif and most other places. The only other thing you need to watch out for is that you have to stay in the same type of vehicle - car engines swapped into cars and truck engines swapped into trucks. There are different allowable emissions levels for cars, light duty trucks, and heavy duty trucks. That's why you need to stay with the same type of vehicle as a donor.

This might be a problem if the Yukon is under 8,500 lb GVW and the Suburban is over. I believe that's the cutoff for "light duty" vs. "heavy duty" emissions and you can't legally put a "heavy duty" motor in a "light duty" vehicle.

Otherwise, both of these vehicles (97 Yukon and 98 Suburban) are old body style, so the frames are the same and the big block should be a bolt in. Keep the computer, harness, and trans from the 98 and it should be fine.
 
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