Hello, idk if this may have been posted before by somebody else but I’m going stir crazy here trying to figure out what I can do, I have a 5.3 motor out of a 08-09 GMC Yukon that preferably I would want to put it in my 3rd gen but I’m having trouble finding the legality aspects to be able to do it. So can I do it? Or do I need to find a new motor? Or can I build up the block differently I’ve been told an lsx but I have no clue what that is 😅

 

Not legal in CA. Can't put a truck motor into a car. It'll never make it past the referee.

The 5.3 IS one of the "LSx" motors. So named after the LS1, the 1st one. All the main parts interchange within that group of engines, much like the small block Chevy from days gone by. Nearly all of the GM V8 engines from the 2000s are "LSx". The 5.3 itself (most of them that is, but not all) have cast-iron blocks though, whereas the original LS1 was aluminum. It's possible to bore out most of the iron 4.8/5.3 blocks to the LS1 bore which makes that motor a 5.7; about 346 CID.

Car motors in the "LSx" series include the LS1 (duh); LS6 which was in Vettes, F bodies, and CTS-V in the early 2000s; LS2 which came later in the early 2000s in Vettes, GTO/G8, and CTS-V; LS7 in Vettes, which is very close to the race motors from those days including a dry sump setup; and LS3, which is the newer square-port head design, in the later 2000s and early 2010s. LSA and LS9 were also used later on, which come from the factory with blowers. You're probably gonna need some one of those instead of a truck motor.

 

You said it was possible to bore out the motor that I have into LS1 specifications so would that the best option or would I definitely need to get a different block entirely

 

The problem isn't so much the "block", or the bore dia, as it is everything else around it. Intake, ECM, all the various devices, etc. The referee isn't going to be concerned about the CID; rather, about the complete engine's documented (factory) compliance with the emissions spec for CARS, which are much stricter than the ones for TRUCKS. I doubt they would bother themselves over the extra or missing 20 cubes; that's not the problem. That said though, they'll look extra hard at ANYTHING that's been swapped out, especially to something that in and of itself isn't allowed.

Personally I'd strongly recommend not tempting fate that way.

Furthermore you'll need a transmission that is legal (i.e., that came) in a CAR of whatever year ENGINE you get. Since there's no difference in let's say a 4L60E from a car vs a truck, other than whether it has the torque arm mount on the extension housing, you could probably get away with a 4L65E instead (5-gear planetaries instead of 4) if you could either come up with the right extension housing, or use a crossmember / torque arm solution that mounts the TA somewhere besides on the transmission. That in turn means you'd need an engine from years that a 4L60E was available. Otherwise with a newer engine you'll be faced with putting in a matching newer transmission such as 6L80E or whatever, some of which are not at all easy to fit into these cars. Then you end up with the issue of making the body electronics match up to the engine ones. It's a potential can of worms.

Another possible route might be a Connect & Cruise package. Not cheeeeep, but dodges many of these issues, since what you're doing is what they're made for.

 

Also, if I'm not mistaken, a motor out of an 08/09 Yukon has AFM.....and you don't want any of that crap.

Another option that wasn't mentioned was to leave California.

 

Your best and easier LS swap in CA is the LS3 E-ROD swap, but its like $12-$15k dollars.

 

That's in the group of things with the Connect & Cruise packages... factory certified and ready to install, with emissions certification already in hand.

 

I have read the connect and cruise packages are not exactly legal in California either. The few people that have tried them have had an absolute nightmare getting them through the referee process.