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1979 Sedan Deville
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448 Posts
Discussion Starter #1
I want to swap an LH2 into my 79, and I live in California where I still have to pass smog. I'm allowed to swap in any car engine (not truck) from any car the same year or newer than my car, provided I also swap over all of the emissions equipment, so the LH2 is a legal swap.

I'm aware that I will need to fabricate engine/transmission mounts, and get a custom drive shaft, and may need to notch my crossmember too.

I'm aware that I will need to do lots of custom wiring, but I think I will enjoy that part.

I'm worried that I will be required to install gauges from an STS in order to do it, but I really don't want to. I'm hoping that I can somehow hack something up so that I can use my 1979 instruments/tell-tale lights to the CARB's satisfaction.

I'm hoping I can use the original TH-400 shift detents on the steering column with the 6L50.

I know an LSx engine would make a lot more sense, as the same swap has basically been done into many very similar cars, but I'm not sure if I want to go that route yet. I want to investigate this first.

madtuners.com appears to have the ability to reprogram the LH2 computers in just about every way, so I could get rid of anti-theft, active suspension, etc, so I could just control the engine and transmission without throwing codes.

If I ever wanted to upgrade the engine, I could just turn to chrfab.com and get some cams and heads and what not, but I think the stock engine will be fine for me. The 425 accelerates me to 60 in about 11 seconds, and the car weighs about the same as an SRX, so should be as fast with the same engine. Right?

Any thoughts?
 

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2007 STS-V
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193 Posts
Re: Northstar swap in 1979 Deville

So lots of issues to consider. My main concern would be the electronics. I would be sure they can in fact mod the ECU. Without this, you will have to have a
custom ECU to deal with the VVT, not to mention the drive by wire. My understanding is the early 2005 LH2 ECU cannot be reprogrammed. 2007 on can be.
The 2005 was a 5 speed, the 6L50 was not installed until early to mid 2006. Different electronics. The 5 speed was made in FRANCE!
 

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08 STS4 V8 1SG & 04 SRX4 V8 & 01 Monte SS
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4,988 Posts

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1979 Sedan Deville
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448 Posts
Discussion Starter #4
Re: Northstar swap in 1979 Deville

I'm not sure if I would NEED the 6L80, but it would probably be safer. The SRX had the 6L50, weighed between 4,100 and 4,400 lbs, and could tow 2,000 more lbs, so it might be fine. Then again it also only got 13 - 20 mpg, and I get 16 mpg with the stock 425... maybe I didn't think this through well enough yet.
 

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2007 STS-V
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193 Posts
Re: Northstar swap in 1979 Deville

Interesting link on madtuner. Good to know. Thanks. Keep in mind the bellhousing is different on the Northstar. 5L50, 6L50, 6L80 (4.4) came set up for
Northstar, but you need to find them. 6L90 was behind the LS series engines so it would require a bellhousing swap.
 

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05 STS4
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4,241 Posts
Frnkbooth said:
Interesting link on madtuner. Good to know. Thanks. Keep in mind the bellhousing is different on the Northstar. 5L50, 6L50, 6L80 (4.4) came set up for Northstar, but you need to find them. 6L90 was behind the LS series engines so it would require a bellhousing swap.
I've done a lot of the test tuning for Mad Tuner.

Highly recommended.

The trans tune makes it a whole different car.

Tellm 1bad set you and hell hook you up with my tune.
 
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