LS engine swap

I've just been thinking about, "What if..." these days. I have a used LS1 that I swapped out of my '98 Firebird for an LS6. I was thinking that if I didn't use it in my old car it would be a good swap in my 3T when the time came. One problem with that idea since I looked closer at the situation; pre-'05 engines used a 24X reluctor wheel on the crank and newer engines used a 58X reluctor wheel. The later system used a quicker ECM. The newer engines are generally DBW (drive-by-wire) vs. the older engines DBC (drive-by-cable). This is something I didn't think about 'til now. The LS6 engine I installed in my Firebird was DBW and I never really gave it a thought until now. That engine was one of the exceptions since it had a 24X reluctor wheel on the crank with an electronic throttle body. When I installed the engine I used the LS1 intake manifold w/ EGR and DBC throttle body and didn't have any issues other than the program of the ECM. So effectively, any engine swaps to be considered in my 3T must be forward compatible ('06 and newer).

You would run into smog issues in California being that the engine is older than the vehicle and need to register it out of state.

Actually what's to determine whether '86 SBC is any different than a '94 SBC or an LS1 long block is different than an LH8 long block (no VVT on either one)? It's all the add-ons like intake and exhaust manifolds, etc. Bolt up all the 5.3L equipment on an LS1 and there you go. My main point was that is prohibited due to the 24X reluctor wheel so I'm stuck on using this engine in an '04 and older vehicle.

I'm pretty sure you can swap out the reluctor wheel, I don't think the block clearances or the sensor position is any different between the gen3 and gen 4 blocks. You will also need the corresponding sensor. A shop should do the reluctor wheel swap.

Another issue you'll need to address is the cam position sensor, gen3 its on the back of the block, gen4 its on the front and uses a different timing chain cam gear that has 4x signal instead of the 2x. I'd imagine you can get the gen4 cam gear (you can get them for both the 1 bolt and 3 bolt cams, I'm using the 3 bolt on mine since the Comp cam I got is a 3 bolt), timing cover, sensor, and sensor cable extension and swap those in and block off the rear sensor (maybe just leave the old sensor in place, not sure if they make actual block off plates for that).

Knock sensors are also in different locations, gen3 is in the valley and gen4 are on the bottom sides of the block.

Other than that everything is pretty much the same until you get into the heads and floating vs pressed fit piston wrist pins.

So with all the sensor changes you'll just need to either modify the existing harness to reach the new locations, or pick up a oem harness for an Alpha.

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I think the Gen III and Gen IV engine differences are significant enough that I wouldn't try a swap like this in Calif. I'd love to have an LS engine connected to my M5 but that's just my wishful thinking. For now my I5 runs great; using a little more oil these days at 115K miles but I'm living with it.

I'm following the other LS engine swap on the site and it's been educational. Seems the Gen IV engines came into use from 2005-2007 and it looks like getting a Gen III crate engine isn't possible any longer. I'm lucky I got my LS6 when I did. I think a practical swap with a Gen IV engine would be an LS3 which is more engine than these vehicles need. I'd want to stay away from any VVT or DOD equipment or software to override that hardware in the engine. I'm not aware of any other Gen IV engines that don't have DOD or VVT and it looks like a crate LH8 isn't available any longer.

Mr_Rich said:

I'm following the other LS engine swap on the site and it's been educational. Seems the Gen IV engines came into use from 2005-2007 and it looks like getting a Gen III crate engine isn't possible any longer. I'm lucky I got my LS6 when I did. I think a practical swap with a Gen IV engine would be an LS3 which is more engine than these vehicles need. I'd want to stay away from any VVT or DOD equipment or software to override that hardware in the engine. I'm not aware of any other Gen IV engines that don't have DOD or VVT and it looks like a crate LH8 isn't available any longer.

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Doesn't fully matter if it comes without AFM or VVT, they are easy to delete. AFM just needs 8 new standard lifters and the non-AFM valley cover and gasket set. VVT is just a matter of replacing the cam and timing cover with the non-VVT versions. Makes it a bit more expensive, but not by a whole lot.

You can get the LS2 with the same configuration as the 5.3 Alpha without the VVT, crate. You can use the entire top end of the Alpha 5.3 on that as well.


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fanugy said:

You can get the LS2 with the same configuration as the 5.3 Alpha without the VVT, crate. You can use the entire top end of the Alpha 5.3 on that as well.


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LS2 engine is Gen III with a 24X reluctor wheel. Not an option in the idea stage of this swap.